Carbonate hardness

Carbonate hardness, is a measure of the water hardness caused by the presence of carbonate () and bicarbonate () anions. Carbonate hardness is usually expressed either in degrees KH (dKH) (from the German "Karbonathärte"), or in "parts per million calcium carbonate" ( ppm or grams per litre|mg/l). One dKH is equal to 17.848 mg/l (ppm) , e.g. one dKH corresponds to the carbonate and bicarbonate ions found in a solution of approximately 17.848 milligrams of calcium carbonate() per litre of water (17.848 ppm). Both measurements (mg/l or KH) are usually expressed as mg/l – meaning the concentration of carbonate expressed as if calcium carbonate were the sole source of carbonate ions.
An aqueous solution containing 120 mg NaHCO3 (baking soda) per litre of water will contain 1.4285 mmol/l of bicarbonate, since the molar mass of baking soda is 84.007 g/mol. This is equivalent in carbonate hardness to a solution containing 0.71423 mmol/L of (calcium) carbonate, or 71.485 mg/l of calcium carbonate (molar mass 100.09 g/mol). Since one degree KH = 17.848 mg/L CaCO3, this solution has a KH of 4.0052 degrees.
Carbonate hardness should not be confused with a similar measure Carbonate Alkalinity which is expressed in either [milli[equivalent]s] per litre (meq/L) or ppm. Carbonate hardness expressed in ppm does not necessarily equal carbonate alkalinity expressed in ppm.
formula_1
whereas
formula_2
However, for water with a pH below 8.5, the CO32− will be less than 1% of the HCO3− so carbonate alkalinity will equal carbonate hardness to within an error of less than 1%.
In a solution where only CO2 affects the pH, carbonate hardness can be used to calculate the concentration of dissolved CO2 in the solution with the formula CO2 = 3 × KH × 10(7-pH), where KH is degrees of carbonate hardness and CO2 is given in ppm by weight.
The term "carbonate hardness" is also sometimes used as a synonym for temporary hardness, in which case it refers to that portion of hard water that can be removed by processes such as boiling or lime softening, and then separation of water from the resulting precipitate.


Fluorosulfite

Fluorosulfite is an ion with the formula SO2F−. The term is also used for compounds or salts containing this group.
Fluorosulfite was discovered in 1953 by F Seel and H Meier.
Organic compounds with the name "fluorosulfite" contain the group -O-SFO.
Preparation.
[((CH3)2N)3SO][SO2F] can be prepared from OSF4 and Me3SiNMe2. Alkali metal fluorosulfites can be made by soaking the metal fluoride in liquid sulfur dioxide for a few days. β-CsSO2F converts to α-CsSO2F when heated to 110 °C for a couple of days but remains stable below 50 °C.
Properties.
The fluorosulfite ion is tetrahedral, with sulfur at the top. The oxygen to sulfur bonds are 147.8 pm and the fluorine to sulfur bond is >169.0 pm long. In solid ionic fluorosulfites, the ion is not fixed in orientation and continuously turns around resulting in dynamic disorder. At room temperature this turning rate is from 2×105 to 107 Hz. When cooled the rate of rotation slows, and can be frozen in place, resulting in static disorder.
Fluorosulfite is isoelectronic with chloryl fluoride (ClO2F) and in compounds it resembles chlorate (ClO3−).
The heat of formation from fluoride (F−) and sulfur dioxide SO2) is 50 kcal mol−1.
Reactions.
Fluorosulfites can react with chlorophosphazenes to make fluorophosphazenes:
Related.
Fluorosulfite is in the category of halosulfite ions which include chlorosulfite, bromosulfite and iodosulfite. Related ions include cyanosulfite SO2CN−.


Silver molybdate

Silver molybdate (Ag2MoO4), a chemical compound, is a yellow, cubic crystalline substance often used in glass. Its crystals present two types of electronic structure, depending on the pressure conditions to which the crystal is subjected. At room temperature, Ag2MoO4 exhibits a spinel-type cubic structure, known as β-Ag2MoO4, which is more stable in nature. However, when exposed to high hydrostatic pressure, the tetragonal α-Ag2MoO4 forms as a metastable phase.
Synthesis and properties.
Research published in 2015 reported the formation of α-Ag2MoO4 by solution-phase precipitation under ambient conditions, using 3-bis(2-pyridyl)pyrazine (dpp) as a doping agent. The influence of the pH of the starting solution on the growth and formation processes of distinct heterostructures (brooms, flowers and rods) was investigated by Singh "et al". and Fodjo "et al"., in which sodium borohydride was employed to induce the reduction of silver nanoparticles on the surface of Ag2MoO4 crystals in order to enhance Raman scattering. In other studies, Ag-Ag2MoO4 composites prepared by microwave-assisted hydrothermal synthesis presented interesting photocatalytic activity for the degradation of rhodamine B under visible light. In addition, Ag2MoO4 mixed with graphite acts as a good lubricant for Ni-based composites, improving the tribological properties of this system. Different synthetic methods have been employed to obtain pure β-Ag2MoO4 crystals, including solid-state reaction or oxide mixture at high temperature, melt-quenching, and Czochralski growth. Particularly, high temperatures, long processing times, and/or sophisticated equipment are necessary in these synthetic routes. Moreover, the final products may be composed of irregular particle shapes with nonhomogeneous size distribution as well as contain the presence of secondary phases. In recent years, pure β-Ag2MoO4 crystals have been synthesized by co-precipitation, microwave-assisted hydrothermal synthesis, a dynamic template route using polymerization of acrylamide assisted templates, and an impregnation/calcination method.
In 2015, the literature reported the formation of β-Ag2MoO4 crystals using different chemical solvents in the reaction medium. These β-Ag2MoO4 microcrystals were synthesized by the precipitation method, employing several polar solvents: deionized water (H2O), methanol (CH4O), ethanol (C2H6O), 1-propanol (C3H8O) and 1-butanol (C4H10O) at 60 °C for 8 h. X-ray diffraction (XRD), Rietveld refinements and field emission scanning electron microscopy (FESEM) were employed in structural and morphological characterizations. Moreover, some researchers have investigated new ways to improve the photocatalytic properties of β–Ag2MoO4 crystals through hydrothermal processing at different temperatures (100, 120, 140 and 160 °C) for 2 h and replacement of Ag atoms by Zn to formation of silver zinc molybdate [β–(Ag2−2xZnx)MoO4] microcrystals by a sonochemical method at 30 °C for 3 h. These new crystals were able to degrade the organic cationic dye rhodamine B and the anionic dye Remazol Brilliant Violet 5R


Chromium(II) hydride

Chromium(II) hydride, systematically named chromium dihydride and poly(dihydridochromium) is pale brown solid inorganic compound with the chemical formula (also written or ). Although it is thermodynamically unstable toward decomposition at ambient temperatures, it is kinetically metastable.
Chromium(II) hydride is the second simplest polymeric chromium hydride (after chromium(I) hydride). In metallurgical chemistry, chromium(II) hydride is fundamental to certain forms of chromium-hydrogen alloys.
Nomenclature.
The systematic name "chromium dihydride", a valid IUPAC name, is constructed according to the compositional nomenclature. However, as the name is compositional in nature, it does not distinguish between compounds of the same stoichiometry, such as molecular species, which exhibit distinct chemical properties. The systematic names poly(dihydridochromium) and poly[chromane(2)], also valid IUPAC names, are constructed according to the additive and electron-deficient substitutive nomenclatures, respectively. They do distinguish the titular compound from the others.
Dihydridochromium.
Dihydridochromium, also systematically named chromane(2), is a related compound with the chemical formula (also written ). It is both thermodynamically and kinetically unstable at ambient temperature with the additional propensity to autopolymerise, and so cannot be concentrated.
Dihydridochromium is the second simplest molecular chromium hydride (after hydridochromium), and is also the progenitor of clusters with the same stoichiometry. In addition, it may be considered to be the chromium(II) hydride monomer.
Molecular chromium(II) hydrides with the formulae and have been isolated in solid gas matrices. The molecular hydrides are very unstable toward thermal decomposition. CrH2 is the major primary product in the reaction of laser-ablated chromium with molecular hydrogen. Dihydridochromium is the most hydrogenated, groundstate classical molecular hydride of chromium. In the presence of pure hydrogen, dihydridochromim readily converts to bis(dihydrogen)dihydridochromium, CrH2(H2)2 in an exothermic reaction.
Properties.
Acidity.
An electron pair of a Lewis base can join with the chromium centre in dihydridochromium by adduction:
Because of this capture of an adducted electron pair, dihydridochromium has Lewis acidic character. Dihydridochromium is a strong Lewis acid with the capacity to capture at least five electron pairs from Lewis bases.
It should be expected that chromium dihydride clusters and chromium(II) hydride have similar acid properties, although reaction rates and equilibrium constants are different.
Structure.
In diluted chromane(2), the molecules are known to oligomerise forming at least dichromane(4) (dimers), being connected by covalent bonds. The dissociation enthalpy of the dimer is estimated to be 121 kJ mol−1. CrH2 is bent, and is weakly repulsive to one hydrogen molecule, but attractive to two molecules of hydrogen. The bond angle is 118±5°. The stretching force constant is 1.64 mdyn/Å. The dimer has a distorted rhombus structure with "C"2"h" symmetry.
Production.
Dichromane(4) is produced synthetically by hydrogenation. In this process, chromium and hydrogen react according to the reaction:
This process involves atomic chromium as an intermediate, and occurs in two steps. The hydrogenation (step 2) is a spontaneous process.
In an inert gas matrix atomic Cr reacts with H2 to make the dihydride when it is irradiated with ultraviolet light between 320 and 380 nm. The reaction of chromium with molecular hydrogen is endothermic. 380 nm or greater wavelength radiation is required to procure photochemically generated CrH2.
History.
In 1979 the simplest molecular chromium(II) hydride with the chemical formula (systematically named chromane(2) and dihydridochromium) was synthesised and identified for the first time. It was synthesised directly from the elements, in a reaction sequence which consisted of simultaneous sublimation of chromium to atomic chromium and thermolysis of hydrogen, and concluded with codeposition in a cryogenic argon matrix to form chromane(2).
In 2003 the dimer with the chemical formula (systematically named dichromane(4) and di-μ-hydrido-bis(hydridochromium)) was synthesised and identified for the first time. It was also synthesised directly from the elements, in a reaction sequence which consisted of laser ablation of chromium to atomic chromium, followed by codeposition with hydrogen in a cryogenic matrix to produce chromane(2), and concluded with annealing to form dichromane(4).


Zirconium(III) chloride

Zirconium(III) chloride is an inorganic compound with formula ZrCl3. It is a blue-black solid that is highly sensitive to air.
Preparation.
The material was first claimed by Ruff and Wallstein who reduced zirconium tetrachloride with aluminium to give impure samples. Subsequently, the problem with aluminium contamination was solved when it was prepared by reduction using zirconium metal:
When aluminium is used as the reducing agent with zirconium tetrachloride, a series of choloroaluminates are formed, for example [Zr(AlCl4)2(AlCl4)2] and Zr(AlCl4)3.
Since the trihalides, such as zirconium trichloride, are comparatively nonvolatile, contamination can be avoided by using a gaseous reductant. For example, zirconium trichloride can be prepared by reduction of zirconium tetrachloride with hydrogen.
Structure.
Some zirconium halides (ZrCl3, ZrBr3, and ZrI3) have structures similar to HfI3. They also have similar space group (P63/mcm) and hexagonal structure with 2 molecules in the cell. The magnetic susceptibility of zirconium trichloride suggests metal-metal interactions of the unpaired electron on each Zr(III) center. The magnetic moment of ZrCl3 (0.4 BM) indicates considerable overlap of metal orbitals.


Silver sulfate

Silver sulfate (Ag2SO4) is an ionic compound of silver used in silver plating and as a non-staining substitute to silver nitrate. This sulfate is stable under ordinary conditions of use and storage, though it darkens upon exposure to air or light. It is minimally soluble in water.
Preparation and structure.
Silver sulfate is prepared by adding sulfuric acid to a solution of silver nitrate:
The compound adopts the structure seen for anhydrous sodium sulfate.
Silver(II) sulfate.
The synthesis of silver(II) sulfate (AgSO4) with a divalent silver ion instead of a monovalent silver ion was first reported in 2010 by adding sulfuric acid to silver(II) fluoride (HF escapes). It is a black solid that decomposes exothermally at 120 °C with evolution of oxygen and the formation of the pyrosulfate.


LE-5

The LE-5 liquid rocket engine and its derivative models were developed in Japan to meet the need for an upper stage propulsion system for the H-I and H-II series of launch vehicles. It is a bipropellant design, using LH2 and LOX. Primary design and production work was carried out by Mitsubishi Heavy Industries. In terms of liquid rockets, it is a fairly small engine, both in size and thrust output, being in the 89 kN (20,000 lbf) and the more recent models the 130 kN (30,000 lbf) thrust class. The motor is capable of multiple restarts, due to a spark ignition system as opposed to the single use pyrotechnic or hypergolic igniters commonly used on some contemporary engines. Though rated for up to 16 starts and 40+ minutes of firing time, on the H-II the engine is considered expendable, being used for one flight and jettisoned. It is sometimes started only once for a nine-minute burn, but in missions to GTO the engine is often fired a second time to inject the payload into the higher orbit after a temporary low Earth orbit has been established.
The original LE-5 was built as a second stage engine for the H-I launch vehicle. It used a fairly conventional gas generator cycle.
LE-5A.
The LE-5A was a heavily redesigned version of the LE-5 intended for use on the new H-II launch vehicle's second stage. The major difference is that the operation of the engine was switched from the gas generator to expander bleed cycle. The LE-5A was the first expander bleed cycle engine to be put into operational service. Cryogenic liquid hydrogen fuel for the cycle is drawn through tubes and passages in both the engine's nozzle and combustion chamber where the hydrogen heats up incredibly while simultaneously cooling those components. The heating of the initially cold fuel causes it to become significantly pressurized and it is utilized to drive the turbine for the propellant pumps.
LE-5B.
The LE-5B was a further modified version of the LE-5A. The changes focused on lowering the per-unit cost of the engine while continuing to increase reliability. The modifications veered towards simplification and cheaper production where possible at the cost of actually lowering the specific impulse to 447 seconds, the lowest of all three models. However, it produced the highest thrust of the three and was significantly cheaper. The primary change from the 5A model was that the 5B's expander bleed system circulated fuel around only the combustion chamber as opposed to both the chamber and the nozzle in the 5A. Alterations to the combustion chamber cooling passages and constituent materials were made with special emphasis on effective heat transfer to allow this method to be successful.
LE-5B-2.
After flight F5 of H-IIA on March 28, 2003 resulted in severe (although not damaging) vibration of the upper stage during LE-5B firing, work was initiated on an upgraded version of the LE-5B. The upgraded engine, named LE-5B-2, was first flown on a H-IIB on September 10, 2009. The main fixes were adding flow-laminarizing plates in the expander manifold, a new mixer of gaseous and liquid hydrogen in the hydrogen feed line, and a new injector plate with 306 smaller coaxial injectors (versus 180 in LE-5B). See LE-5B-2 development summary (Japanese).
The upgrade reduced the vibrations produced by the upper stage by half.
LE-5B-3.
For the new H3 launch vehicle, the veteran design of the LE-5B was once again revisited. To meet the requirements of the H3 and to ensure a stable supply of parts over H3's lifetime, performance was to be improved and costs were to be lowered, all while keeping development risk as low as possible. Obsolete parts that were becoming hard to acquire such as the electronics in the engine controller were to be replaced with modern components that could be reliably sourced for years to come, and the manufacturing method for the combustion chamber was to be likewise updated for similar reasons. The liquid hydrogen turbopump and turbine nozzle were to be updated for H3's longer mission duration times, and the performance of the liquid oxygen turbopump and fuel mixer was to be improved.
The first example of the updated design was test fired in March, 2017. The engine's certification for flights on the H3 rocket are currently ongoing.
Specifications.
.* = tank head pressure only


New Jersey Zinc Company


Zippeite

Zippeite is a hydrous potassium uranium sulfate mineral with formula: K4(UO2)6(SO4)3(OH)10·4(H2O). It forms yellow to reddish brown monoclinic-prismatic crystals with perfect cleavage. The typical form is as encrustations and pulverulent earthy masses. It forms as efflorescent encrustations in underground uranium mines. It has a Mohs hardness of 2 and a specific gravity of 3.66. It is strongly fluorescent yellow under ultraviolet light and is moderately radioactive.
Historical usage.
A mineral which caught the attention of a Bohemian metallurgist, Adolf Patera, in the 1850s by its striking colour. It was named after the Austrian mineralogist Franz Xaver Maximilian Zippe (1791–1863). This was during the period when the fame of the Jachymov silver mines was dying out. On top of the large, forgotten pit-heaps, powdery minerals began to appear, vividly coloured, originating from the decomposition of the pitchblende. These colourful layers, in which zippeite was in the majority, gave Patera the idea of utilizing the uranium minerals in the manufacture of paints. Mining began in 1859 not only for the products which resulted from uraninite's decomposition, but for uraninite itself. A variety of yellow paints were manufactured because among all the secondary minerals on the pit-heap there was a prevalence of the yellow powdery coatings.
Zippeite is one of the so-called 'uranium ochres'. It occurs in association with uranopilite, a monoclinic, complex water-soluble alkaline with other secondary uranium minerals in the weathered veins of uranium. Apart from Jachymov in Bohemia it occurs mainly near Wölsendorf in Bavaria (Germany) and also in the US states of Utah and New Mexico. Zippeite is no longer used for the manufacture of paints, but is still used as a source of depleted uranium.


Iodomethylzinc iodide

Iodomethylzinc iodide is the active reagent in the Simmons–Smith reaction. For example, iodomethylzinc iodide, formed "in situ" from diiodomethane and a zinc-copper couple reacts with cyclohexene to give norcarane (bicyclo[4.1.0]heptane).
Iodomethylzinc iodide may also be generated by the reaction of diazomethane with zinc iodide, or by the reaction of methylene iodide with diethylzinc.


Unbioctium


Karlite

Karlite (kar'-lite) is a silky white to light green orthorhombic borate mineral, not to be confused with tremolite-actinolite. It has a general formula of Mg7(BO3)3(OH)4Cl. Karlite is named in honor of Franz Karl (1918–1972), professor of mineralogy and petrography at Christian Albrechts University in Kiel, Germany, for his studies of the geology of the eastern Alps.
Karlite possesses moderate optical relief, the degree to which the mineral grains stand out from the mounting medium. This mineral is orthorhombic and sphenoidal, exhibiting symmetry on 222. Karlite is also enantiomorphic and dihedral. It is a member of the P212121 space group. This mineral forms optically negative biaxial birefringent crystals, meaning that the 2V angle between the optic axes is bisected by the refractive index direction. Because this mineral possesses birefringence, we know it is anisotropic and will display double refraction; it breaks light into two different rays traveling at different speeds in the mineral.
Karlite is a relatively newly discovered borate mineral occurring in clinohumite-chlorite marble in calcsilicate-carbonate lenses embedded in amphibolite. The amphibole at the original locale is situated between tectonic units "Zentralgneis" and "Schieferhulle". Scholars assume that the high boron concentration needed for the formation of karlite is due to a contact metasomatism created by Hercynian tonalitic magmas, which make up the "Zentralgneis", although the boron content of karlite is not of commercial importance. This mineral was originally discovered in the Furtschaglkar near the Furtschaglhaus in Austria, but has also been found in Russia and France, and was probably formed during the alpine metamorphism of the Alps.


Silylenoid

A Silylenoid in organosilicon chemistry is a type of chemical compound with the general structure R2SiXM where R is any organic residue, X a halogen and M a metal. Silylenoids are the silicon pendants of carbenoid and both compounds have carbene or silylene like properties.
Silylenoids are encountered as reactive intermediates in chemical reactions. A stable silylenoid can be prepared by reaction of a fluorobromosilane with a silyllithium compound in THF :
In this silylenoid the silicon atom is bonded with three substituents and not the usual four. X-ray diffraction shows that the Si-F bond with 170 pm is longer than usual for fluorosilanes. The F-Li bond is ionic with an estimated (in silico) positive charge of 0.88 residing on lithium and a negative charge of 0.74 on fluorine making it a t-Bu2MeSi)2SiF−, Li+.3THF salt. The Si-F bond is likewise polarized with only 10% of the charge on silicon.
When the silylenoid is irradiated or heated a disilene forms probably via a silylene intermediate. With electrophiles it reacts as an anion and with organolithium compounds it reacts as a silylene.


Crockern Tor

Crockern Tor is a tor in Dartmoor National Park, Devon, England. Composed of two large outcrops of rock, it is 396 metres above sea level. The lower outcrop was the open-air meeting place of the Stannary Convocation of Devon from the early 14th century until the first half of the 18th century. On Parliament Rock, pictured here, the Lord Warden of the Great Court of the Devon Tinners supposedly sat during meetings of the Court.
Descriptions.
The tor was one of only three features on Dartmoor that Tristram Risdon considered important enough to include in his "Survey of Devon" which was compiled in the early 17th century. In it he said that "Crockern Torr" had "a table and seats of moorstone [granite], hewn out of the rocks, lying in the force of all weather, no house or refuge being near it". The tor was also one of the few historic features to appear on Benjamin Donn's one inch to the mile map of Devon of 1765. It lies adjacent to the trans-Dartmoor packhorse track, so was a significant landmark for travellers since time immemorial.
Stannary court.
The tor was the hub of the four Dartmoor stannary areas – Ashburton, Chagford, Tavistock and Plympton – whose boundaries radiate outwards from it. The Stannary Court was convoked here when deemed necessary, at irregular intervals, by the Lord Warden who summoned 24 representatives or "jurates" from each of the four stannaries. Each meeting probably continued for several days and dealt with matters such as setting stannary law, registering tinworks and mills, hearing petitions and imposing penalties on those guilty of breaking the stannary laws.
There is evidence for ten assemblies at Crockern Tor: in 1494, 1510, 1532, 1533, 1552, 1567, 1574, 1600, 1688 and 1703. The earliest documented meeting on 1 September 1494 had Sir John Stepcote, vice-warden of the Devon Stannaries, as chairman. Sir Walter Raleigh was Lord Warden of the Stannaries for many years, and it is recorded that he presided at one Court at Crockern Tor, on 27 October 1600. The last meeting for which records survive was on 23 September 1703 where the Warden, John Granville, 1st Baron Granville and the Vice-Warden, the Honourable Samuel Rolle, opened the court at 8 a.m. The last court was said to have been held in or around 1745, but no documentation exists, and considering that the tin industry on Dartmoor had by then declined greatly, it could have been only a small affair.
Patchy and conflicting evidence indicates that compared to the bare nature of the site today, there were chairs, seats, a table and a shelter, all made of granite, which were used when the court met. These items were supposedly taken away or broken up in the late 18th century, possibly used as a source of stone for the buildings that started to appear on the moor after the roads were improved. On the other hand, Douglas St Leger-Gordon, the noted writer on Devon history, casts doubt on the existence of any substantial meetings at this "singularly unsuitable" place in his 1963 book, "Portrait of Devon". He points out that any proceedings must have been frequently disrupted by the wind carrying away someone's hat, or "scattering the minutes of the last meeting insecurely held in the warden's numbed fingers". He notes that later records of the Parliament mention adjournments to Tavistock and suggests that a nearby "Tinners' Hall" - now lost - may have been where they actually conducted their business.
Folklore.
Crockern Tor is said to be the home of the mythical Old Crockern, variously described as a spectral figure on horseback, galloping across the moor on a skeleton horse with his phantom hounds which were stabled at nearby Wistman's Wood; or as a local god of the moor in pre-Christian times:


Silenes

Silene, or silalkenes, are unsaturated hydrosilicons, which means that they consist only of hydrogen and silicon atoms and all bond, with the exception of one double bond, are either single or double bonds. By definition cycles are excluded, so that the silenes comprise homologous series of inorganic compounds with the general formula , "k" > 0, where "k" is defined as the number of double bonds. There are no commercial sources.
Each silicon atom has three or four bonds (either Si-H, Si-Si, or Si=Si), and each hydrogen atom is joined to a silicon atom (H-Si bonds). A series of linked silicon atoms is known as the silicon skeleton or silicon backbone. The number of silicon atoms is used to define the size of the silene (e.g. Si-silene).
A "silenyl" group, is a functional group or side-chain with the general formula , "k" > 0, where "k" is defined as the number of double bonds, for example an disilenyl or trisil-1-en-1-yl group.
The simplest silene is (the parent molecule) is disilene, . There is no limit to the number of silicon atoms that can be linked together, the only limitation being that the molecule is acyclic, is unsaturated, and is a hydrosilicon.
For bridged silenes, the Bredt's rule states that a double bond cannot be placed at the bridgehead of a bridged ring system, unless the rings are large enough (8 or more atoms). Aromatic compounds are often drawn as cyclic silenes, but their structure and properties are different and they are not considered to be silenes. Although silenes are mainly of theoretical interest, substituted silenes are well known class of organosilicon compounds.
Structure.
Like single covalent bonds, double bonds can be described in terms of overlapping atomic orbitals, except that, unlike a single bond (which consists of a single sigma bond), a silicon-silicon double bond consists of one sigma bond and one pi bond. This double bond is stronger than a single covalent bond and also shorter.
Each silicon of the double bond uses its three "sp2" hybrid orbitals to form sigma bonds to three atoms. The unhybridized 3"p" atomic orbitals, which lie perpendicular to the plane created by the axes of the three sp² hybrid orbitals, combine to form the pi bond. This bond lies outside the main Si—Si axis, with half of the bond on one side and half on the other.
Rotation about the silicon-silicon double bond is not restricted because it involves breaking the pi bond, which requires a small amount of energy. As a consequence, substituted alkenes may not exist as one of two isomers.
It is certainly possible to twist a double bond.
History.
The first transient disilene was synthesized in 1972 by D. N. Roark and Garry J. D. Peddle. The first thermally stable disilene, tetramesityldisilene, was described in 1981 by West, Fink and Michl. It was prepared by UV-photolysis of the related cyclic trisilane:
Properties.
Simple disilenes are very reactive species and easily undergo polymerization or other reactions, so their life is very short. To prevent this polymerization and other reactions, bulky substituents are used to stabilize disilenes effectively for long-term survival in dilute solution and even in crystals.
Stable disilenes are generally yellow- or orange-colored crystalline compounds.
The Si=Si double bond lengths of disilenes vary between 2.14 and 2.29 Å and are nearly 5 to 10% shorter than the Si-Si single bond lengths of corresponding disilanes.
This rate of bond shortening is less than "ca" 13% in carbon compounds, but is short enough for true double bond characteristics.
A further peculiarity of disilenes is the "trans"-bending of the substituents, which is never observed in alkenes. The "trans"-bent angles of disilenes between the R2Si planes and the Si=Si vector range from 0 to 33.8 °. This distortion is rationalized by the stability of the corresponding silylene fragments, although disilenes do not typically dissociate.
The distorted geometry of disilenes can be rationalized by considering the valence orbitals of silicon, which are 3s and 3p, whereas those of carbon are 2s and 2p. Thus, the energy gap between the "n"s and "n"p orbitals of a silicon atom is larger than that of a carbon atom.
Therefore, silylene fragments are in a singlet state, while carbene fragments are in a triplet state. So, when double bonds are formed by the interaction of these two fragments, disilenes which consist of two silylene units are "trans"-bending and alkenes which consist of two carbene units are planar. The bending is even more extreme for the tin analogues of disilenes.
Synthesis.
Disilenes are generally synthesized by reduction of 1,2-dihalodisilane, by retro-Diels–Alder fragmentation, by dimerization of silylenes, by photofragmentation of cyclopolysilanes, or by rearrangement of silylsilylenes.
A series of 1,1,1,4,4,4-hexaalkyl-2,3-bis(trialkylsilyl)tetrasil-2-enes structural analogues are typically synthesised using reductive coupling of the corresponding 1,1,1,3,3,3-hexaalkyl-2,3-tribromotrisilanes.
Nomenclature.
IUPAC names.
To form the root of the IUPAC names for silenes, simply change the -an- infix of the parent to -en-. For example, - is the silane "disilANe". The name of = is therefore "disilENe".
In higher silenes, where isomers exist that differ in location of the double bond, the following numbering system is used:
Organosilenes.
The organosilenes are a group of chemical compounds derived from silenes containing one or more organic groups. They are a subset of the general class of organosilicons, although the distinction is not often made.


Unbibium

Unbibium, also known as element 122 or eka-thorium, is the hypothetical
chemical element in the periodic table with the placeholder symbol of Ubb and atomic number 122. "Unbibium" and "Ubb" are the temporary systematic IUPAC name and symbol respectively, which are used until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table of the elements, it is expected to follow unbiunium as the second element of the superactinides and the fourth element of the 8th period. Similarly to unbiunium, it is expected to fall within the range of the island of stability, potentially conferring additional stability on some isotopes, especially 306Ubb which is expected to have a magic number of neutrons (184).
Despite several attempts, unbibium has not yet been synthesized, nor have any naturally occurring isotopes been found to exist. There are currently no plans to attempt to synthesize unbibium. In 2008, it was claimed to have been discovered in natural thorium samples, but that claim has now been dismissed by recent repetitions of the experiment using more accurate techniques.
Chemically, unbibium is expected to show some resemblance to cerium and thorium. However, relativistic effects may cause some of its properties to differ; for example, it is expected to have a ground state electron configuration of [Og] 7d1 8s2 8p1 or [Og] 8s2 8p2, despite its predicted position in the g-block superactinide series.
History.
Synthesis attempts.
Fusion-evaporation.
Two attempts were made to synthesize unbibium were in the 1970s, both propelled by early predictions on the island of stability at "N" = 184 and "Z" > 120, and in particular whether superheavy elements could potentially be naturally occurring. The first attempts to synthesize unbibium were performed in 1972 by Flerov "et al." at the Joint Institute for Nuclear Research (JINR), using the heavy-ion induced hot fusion reactions:
Another unsuccessful attempt to synthesize unbibium was carried out in 1978 at the GSI Helmholtz Center, where a natural erbium target was bombarded with xenon-136 ions:
No atoms were detected and a yield limit of 5 nb (5,000 pb) was measured. Current results (see flerovium) have shown that the sensitivity of these experiments were too low by at least 3 orders of magnitude. In particular, the reaction between 170Er and 136Xe was expected to yield alpha emitters with half-lives of microseconds that would decay down to isotopes of flerovium with half-lives perhaps increasing up to several hours, as flerovium is predicted to lie near the center of the island of stability. After twelve hours of irradiation, nothing was found in this reaction. Following a similar unsuccessful attempt to synthesize unbiunium from 238U and 65Cu, it was concluded that half-lives of superheavy nuclei must be less than one microsecond or the cross sections are very small. More recent research into synthesis of superheavy elements suggests that both conclusions are true.
In 2000, the Gesellschaft für Schwerionenforschung (GSI) Helmholtz Center for Heavy Ion Research performed a very similar experiment with much higher sensitivity:
These results indicate that the synthesis of such heavier elements remains a significant challenge and further improvements of beam intensity and experimental efficiency is required. The sensitivity should be increased to 1 fb in the future for more quality results.
Compound nucleus fission.
Several experiments studying the fission characteristics of various superheavy compound nuclei such as 306Ubb were performed between 2000 and 2004 at the Flerov Laboratory of Nuclear Reactions. Two nuclear reactions were used, namely 248Cm + 58Fe and 242Pu + 64Ni. The results reveal how superheavy nuclei fission predominantly by expelling closed shell nuclei such as 132Sn ("Z" = 50, "N" = 82). It was also found that the yield for the fusion-fission pathway was similar between 48Ca and 58Fe projectiles, suggesting a possible future use of 58Fe projectiles in superheavy element formation.
Future.
Every element from mendelevium onward was produced in fusion-evaporation reactions, culminating in the discovery of the heaviest known element oganesson in 2002 and most recently tennessine in 2010. These reactions approached the limit of current technology; for example, the synthesis of tennessine required 22 milligrams of 249Bk and an intense 48Ca beam for six months. The intensity of beams in superheavy element research cannot exceed 1012 projectiles per second without damaging the target and detector, and producing larger quantities of increasingly rare and unstable actinide targets is impractical.
Consequently, future experiments must be done at facilities such as the under-construction superheavy element factory (SHE-factory) at the Joint Institute for Nuclear Research (JINR) or RIKEN, which will allow experiments to run for longer stretches of time with increased detection capabilities and enable otherwise inaccessible reactions.
It is possible that fusion-evaporation reactions will not be suitable for the discovery of unbibium or heavier elements. Various models predict increasingly short alpha and spontaneous fission half-lives for isotopes with "Z" = 122 and "N" ~ 180 on the order of microseconds or less, rendering detection nearly impossible with current equipment. The increasing dominance of spontaneous fission also may sever possible ties to known nuclei of livermorium or oganesson and make identification and confirmation more difficult; a similar problem occurred in the road to confirmation of the decay chain of 294Og which has no anchor to known nuclei. For these reasons, other methods of production may need to be researched such as multi-nucleon transfer reactions capable of populating longer-lived nuclei. A similar switch in experimental technique occurred when hot fusion using 48Ca projectiles was used instead of cold fusion (in which cross sections decrease rapidly with increasing atomic number) to populate elements with "Z" > 113.
Nevertheless, several fusion-evaporation reactions leading to unbibium have been proposed in addition to those already tried unsuccessfully, though no institution has immediate plans to make synthesis attempts, instead focusing first on elements 119, 120, and possibly 121. Because cross sections increase with asymmetry of the reaction, a chromium beam would be most favorable in combination with a californium target, especially if the predicted closed neutron shell at "N" = 184 could be reached in more neutron-rich products and confer additional stability. In particular, the reaction between and would generate the compound nucleus and reach the shell at "N" = 184, though the analogous reaction with a target is believed to be more feasible because of the presence of unwanted fission products from and difficulty in accumulating the required amount of target material. One possible synthesis of unbibium could occur as follows:
Should this reaction be successful and alpha decay remain dominant over spontaneous fission, the resultant 300Ubb would decay through 296Ubn which may be populated in cross-bombardment between 249Cf and 50Ti. Although this reaction is one of the most promising options for the synthesis of unbibium in the near future, the maximum cross section is predicted to be 3 fb, one order of magnitude lower than the lowest measured cross section in a successful reaction. The more symmetrical reactions 244Pu + 64Ni and 248Cm + 58Fe have also been proposed and may produce more neutron-rich isotopes. With increasing atomic number, one must also be aware of decreasing fission barrier heights, resulting in lower survival probability of compound nuclei, especially above the predicted magic numbers at "Z" = 126 and "N" = 184.
Claimed discovery as a naturally occurring element.
In 2008, a group led by Israeli physicist Amnon Marinov at the Hebrew University of Jerusalem claimed to have found single atoms of unbibium-292 in naturally occurring thorium deposits at an abundance of between 10−11 and 10−12 relative to thorium. This was the first time in 69 years that a new element had been claimed to be discovered in nature, after Marguerite Perey's 1939 discovery of francium. The claim of Marinov "et al." was criticized by a part of the scientific community, and Marinov says he has submitted the article to the journals "Nature" and "Nature Physics" but both turned it down without sending it for peer review. The unbibium-292 atoms were claimed to be superdeformed or hyperdeformed isomers, with a half-life of at least 100 million years.
A criticism of the technique, previously used in purportedly identifying lighter thorium isotopes by mass spectrometry, was published in "Physical Review C" in 2008. A rebuttal by the Marinov group was published in "Physical Review C" after the published comment.
A repeat of the thorium experiment using the superior method of accelerator mass spectrometry (AMS) failed to confirm the results, despite a 100-fold better sensitivity. This result throws considerable doubt on the results of the Marinov collaboration with regards to their claims of long-lived isotopes of thorium, roentgenium, and unbibium. It is still possible that traces of unbibium might exist in some thorium samples, though given current understanding of superheavy elements, this is very unlikely.
Naming.
Using Mendeleev's nomenclature for unnamed and undiscovered elements, unbibium should instead be known as "eka-thorium". After the recommendations of the IUPAC in 1979, the element has since been largely referred to as "unbibium" with the atomic symbol of ("Ubb"), as its temporary name until the element is officially discovered and synthesized, and a permanent name is decided on. Scientists largely ignore this naming convention, and instead simply refer to unbibium as "element 122" with the symbol of ("122"), or sometimes even "E122" or "122".
Predicted properties.
Nuclear stability and isotopes.
The stability of nuclei decreases greatly with the increase in atomic number after plutonium, the heaviest primordial element, so that all isotopes with an atomic number above 101 decay radioactively with a half-life under a day, with an exception of dubnium-268. No elements with atomic numbers above 82 (after lead) have stable isotopes. Nevertheless, because of reasons not very well understood yet, there is a slight increased nuclear stability around atomic numbers 110–114, which leads to the appearance of what is known in nuclear physics as the "island of stability". This concept, proposed by University of California professor Glenn Seaborg, explains why superheavy elements last longer than predicted.
In this region of the periodic table, "N" = 184 has been suggested as a closed neutron shell, and various atomic numbers have been proposed as closed proton shells, such as "Z" = 114, 120, 122, 124, and 126. The island of stability would be characterized by longer half-lives of nuclei located near these magic numbers, though the extent of stabilizing effects is uncertain due to predictions of weakening of the proton shell closures and possible loss of double magicity. More recent research predicts the island of stability to instead be centered at beta-stable copernicium isotopes 291Cn and 293Cn, which would place unbibium well above the island and result in short half-lives regardless of shell effects. The increased stability of elements 112–118 has also been attributed to the oblate shape of such nuclei and resistance to spontaneous fission. The same model also proposes 306Ubb as the next spherical doubly magic nucleus, thus defining the true island of stability for spherical nuclei.
A quantum tunneling model predicts the alpha-decay half-lives of unbibium isotopes 284–322Ubb to be on the order of microseconds or less for all isotopes lighter than 315Ubb, highlighting a significant challenge in experimental observation of this element. This is consistent with many predictions, though the exact location of the 1 microsecond border varies by model. Additionally, spontaneous fission is expected to become a major decay mode in this region, with half-lives on the order of femtoseconds predicted for some even–even isotopes due to minimal hindrance resulting from nucleon pairing and loss of stabilizing effects farther away from magic numbers. A 2016 calculation on the half-lives and probable decay chains of isotopes 280–339Ubb yields corroborating results: 280–297Ubb will be proton unbound and possibly decay by proton emission, 298–314Ubb will have alpha half-lives on the order of microseconds, and those heavier than 314Ubb will predominantly decay by spontaneous fission with short half-lives. For the lighter alpha emitters that may be populated in fusion-evaporation reactions, some long decay chains leading down to known or reachable isotopes of lighter elements are predicted. Additionally, the isotopes 308–310Ubb are predicted to have half-lives under 1 microsecond, too short for detection as a result of significantly lower binding energy for neutron numbers immediately above the "N" = 184 shell closure. Alternatively, a second island of stability with total half-lives of approximately 1 second may exist around "Z" ~ 124 and "N" ~ 198, though these nuclei will be difficult or impossible to reach using current experimental techniques. However, these predictions are strongly dependent on the chosen nuclear mass models, and it is unknown which isotopes of unbibium will be most stable. Regardless, these nuclei will be hard to synthesize as no combination of obtainable target and projectile can provide enough neutrons in the compound nucleus. Even for nuclei reachable in fusion reactions, spontaneous fission and possibly also cluster decay might have significant branches, posing another hurdle to identification of superheavy elements as they are normally identified by their successive alpha decays.
Chemical.
Unbibium is predicted to be similar in chemistry to cerium and thorium, which likewise have four valence electrons above a noble gas core, although it may be more reactive. Additionally, unbibium is predicted to belong to a new block of valence g-electron atoms, although the 5g orbital is not expected to start filling until about element 125. The predicted ground-state electron configuration of unbibium is either [Og] 7d1 8s2 8p1 or 8s2 8p2, in contrast to the expected [Og] 5g2 8s2 in which the 5g orbital starts filling at element 121. (The ds2p and s2p2 configurations are expected to be only separated by about 0.02 eV.) In the superactinides, relativistic effects might cause a breakdown of the Aufbau principle and create overlapping of the 5g, 6f, 7d and 8p orbitals; experiments on the chemistry of copernicium and flerovium provide strong indications of the increasing role of relativistic effects. As such, the chemistry of elements following unbibium becomes more difficult to predict.
Unbibium would most likely form a dioxide, UbbO2, and tetrahalides, such as UbbF4 and UbbCl4. The main oxidation state is predicted to be +4, similar to cerium and thorium. A first ionization energy of 5.651 eV and second ionization energy of 11.332 eV are predicted for unbibium; this and other calculated ionization energies are lower than the analogous values for thorium, suggesting that unbibium will be more reactive than thorium.


Kampughat mine

The Kampughat mine is one of the largest magnesium mines in Nepal and in the world. The mine is located in the east of the country in the Sagarmatha Zone. The mine has estimated reserves of 20 million tonnes of ore 30% magnesium.


Statue of Olive Risley Seward

Olive Risley Seward is a lead on burlap statue by American sculptor John Cavanaugh, located at North Carolina Avenue and Sixth Street, Southeast, Washington, D.C., in the Capitol Hill neighborhood.
Completed in 1971, it is a representation of Olive Risley Seward (1841–1908), the foster daughter of William H. Seward.


Trifluoromethyl hypofluorite

Trifluoromethyl hypofluorite is an organofluorine compound with the formula . It exists as a colorless gas at room temperature and is highly toxic. It is a rare example of a hypofluorite (compound with an O−F bond). It is prepared by the reaction of fluorine gas with carbon monoxide:
The gas hydrolyzes only slowly at neutral pH.
Use in organic chemistry.
The compound is a source of electrophilic fluorine. It has been used for the preparation of α-fluoroketones from silyl enol ethers.
Behaving like a pseudohalogen, it adds to ethylene to give the ether:


Cobalt(II) naphthenate

Cobalt(II) naphthenate is a mixture of cobalt(II) derivatives of naphthenic acids. These coordination complexes are widely used as oil drying agents for the autoxidative crosslinking of drying oils. Metal naphthenates are not well defined in conventional chemical sense that they are mixtures. They are widely employed catalysts because they are soluble in the nonpolar substrates, such as the alkyd resins or linseed oil. The fact that naphthenates are mixtures helps to confer high solubility. A second virtue of these species is their low cost. A well-defined compound that exhibits many of the properties of cobalt naphthenate is the cobalt(II) complex of 2-ethylhexanoic acid. Often in technical literature, naphthenates are described as salts, but they are probably also non-ionic coordination complexes with structures similar to basic zinc acetate.
The catalytic properties of cobalt(II) naphthenates are similar to those of related compounds containing manganese and iron. Such species are sometimes classified as active driers. Active driers are catalysts that feature redox-active metal centers. Such centers promote redox reactions with hydroperoxide-containing intermediates.
Toxicity and safety.
Cobalt Naphthenate is a moderately toxic substance which can cause a range of acute and chronic conditions, and it is also a carcinogen. It is most commonly used diluted in mineral spirit or mineral oil. Safety equipment must be used to avoid eye and skin contact. The pure compound has a high vapor density of 3.9 (air = 1), and a low vapor pressure of 1 mm Hg at 25°C (77°F).


Ryazan Plant for Manufacturing and Processing Non-Ferrous Metals

Ryazan Plant for Manufacturing and Processing Non-Ferrous Metals (Ryaztsvetmet; ) is Russia’s chief manufacturer of lead and . In 2009 the plant underwent a full-scale modernization, including the assembling of the modern automatic equipment. This allowed increasing the production and at the same time dramatically decreasing ecological risks: the emission has been reduced by three times, electrical energy consumption – by 3.8 times.
Production.
Ryaztsvetmet produces pure lead (99.97% and 99.985%) and antimony and tin based , as well as custom-made lead alloys with alloying additions.
Ryaztsvetmet offers a selection of lead powder and feathered tin, solder alloys, Babbitts, lead pipes and goods (anodes & wires)
The plant also sells crushed polypropylene (from discarded automotive batteries).
Shipment.
The products are supplied to manufacturers of accumulator batteries all over the world.
A significant part of the production is sold in the domestic market and used for manufacturing automotive batteries.


Chromium(I) hydride

Chromium(I) hydride, systematically named chromium hydride, is an inorganic compound with the chemical formula (also written as or CrH). It occurs naturally in some kinds of stars where it has been detected by its spectrum. However, molecular chromium(I) hydride with the formula CrH has been isolated in solid gas matrices. The molecular hydride is very reactive. As such the compound is not well characterised, although many of its properties have been calculated via computational chemistry.
Molecular forms.
A. G. Gaydon first created CrH gas with an electric arc between chromium electrodes in a hydrogen air flame.
CrH can be formed by the reaction of chromium metal vapour, created by an electrical discharge in the presence of hydrogen. The electric discharge breaks up the H2 molecules into reactive H atoms. So the reaction then proceeds as Cr(g) + H → CrH.
Another method to make CrH is to react chromium carbonyl (Cr(CO)6) vapour with atomic hydrogen generated by an electric discharge.
Chromium hydride can also be formed by reacting chromium with methane in an electric arc. This also produces a variety of carbon and hydrogen containing chromium molecules such as CrCH3 and CrCCH. Also it is possible to trap CrH into a solid argon noble gas matrix. The solid argon does not react with CrH and allows studying reactive molecules that need to be kept apart from other molecules. The researchers that produced the trapped CrH molecules also believe that they made and trapped CrH2 molecules, based on its spectrum.
Properties.
When produced in the reaction with chromium vapour in an electric discharge, the chromium hydride gas glows with a bright bluish-green colour.
The ground electronic state of CrH is 6Σ+. The outer electronic configuration is σ2σ1δ2π2. The σ2 electron is the bonding electron with hydrogen, and the other electrons are unpaired. The only part of the molecule with nuclear spin, is the proton in the hydrogen. Hyperfine structure of the spectral lines is extremely fine. The Fermi contact term which measures the hyperfine splitting is only -34.43 MHz, whereas for the hydrogen atom it is 1420.40575177 MHz.
The dipole moment of the molecule is 3.864 Debye.
The disassociation energy required to break the molecule into two atoms is 2.118 eV or 1.93 eV.
The CrH molecule is strongly paramagnetic. It can have a lifetime of over 0.1 seconds when it is trapped in 3He cooled to 0.650 K.
Spectrum.
Like other molecules, the CrH molecule can store energy in several ways. Firstly, the molecule can spin with the hydrogen atom seeming to orbit the chromium atom. Secondly, it can vibrate with the two atoms bouncing towards and away from each other. Thirdly, electrons can change from one atomic orbital to another in the chromium atom. All of these can happen at the same time. All the numerous combinations of changes result in many different possible energy changes. Each of these changes will match a frequency in the electromagnetic spectrum which is absorbed. When many of these frequencies cluster together in a group, an absorption band results.
An ultraviolet spectral band between 360 and 370 nm was discovered in 1937.
A6Σ+–X6Σ+ transition is observed in S type stars and sunspots and also L type brown dwarfs.
Submillimeter.
Changes in the rotational rate of the molecule lead to a far-infrared spectrum. N=1→0 transition has line frequencies at 5/2 → 3/2 337.259145 GHz, 5/2 → 7/2 362.617943 GHz and 362.627794 GHz, and 5/2 → 5/2 396.541818 GHz and 396.590874 GHz. N=2→1 735 GHz; N=3→2 at 1.11 THz N=4→3 at 1.47 THz
Kleman & Uhler observed the infrared spectrum and were the first to note absorption bands.
Occurrence in stars.
The existence of CrH in stars was only established in 1980 when spectral lines were identified in S-type stars and sunspots. CrH was discovered in brown dwarfs in 1999. Along with FeH, CrH became useful in classifying L dwarfs. The CrH spectrum was identified in a large sunspot in 1976, but the lines are much less prominent than FeH.
Concentration of CrH in the L5 type of brown dwarf is 3 parts per billion compared to H, whereas the normal abundance of chromium is 0.5 parts per million compared to Hydrogen. In S-type stars a series of unknown lines appeared in the near infrared spectrum. They were termed the Keenan bands based on a spectrum of R Cyg. One of the bands with a band head at 861.11 nm was identified as due to CrH.
CrH is used to classify the L-type brown dwarfs into subtypes L0 to L8. The CrH absorption band is a diagnostic feature of L-type stars. For subtypes of the L-type brown dwarfs, L5 to L8 the CrH band at 861.1 nm is more prominent than the FeH band at 869.2 nm and for L4 these two bands are equally strong. For L0 type stars, TiO lines are similar in strength to CrH lines, and in L1 Ti0 lines are slightly weaker than CrH. L1 to L3 have FeH band stronger than the CrH.
Chromium(II) hydride.
A related chemical compound, is the more stable chromium(II) hydride, identified by Weltner "et al." in 1979 using a solid argon matrix. This compound is susceptible to dimerisation in the gas phase. The dimer is more stable than the monomer by 121 kJ mol−1. Chromium(II) hydride is the most hydrogenated, groundstate classical hydride of chromium. CrH2 is predicted to be bent, rather than linear in shape. The bond angle is 118±5°. The stretching force constant is 1.64 mdyn/Å. In an inert gas matrix atomic Cr reacts with H2 to make the dihydride when it is irradiated with ultraviolet light between 320 and 380 nm. The CAS number is 13966-81-9.
Non-classical hydrides.
Other nonclassical hydrides also exist. They include dihydrogen molecules as a ligand, such as CrH(H2), CrH2(H2), CrH2(H2)2. The nonclassical hydrides are formed by reacting chromium(I) or chromium(II) hydride with dihydrogen gas, with optional inert gas. Chromium trihydride excimer is formed when CrH2(H2) is subjected to green or yellow light.


Thulium(III) chloride

Thulium(III) chloride or thulium trichloride is as an inoriganic salt composed of thulium and chlorine with the formula TmCl3. It forms yellow crystals. Thulium(III) chloride has the YCl3 (AlCl3) layer structure with octahedral thulium ions.
Reactions.
The hydrated form of thulium(III) chloride can be obtained by adding thulium(III) oxide to concentrated hydrochloric acid. Thulium(III) chloride reacts with strong bases to make thulium(III) oxide.


Organochloride

An organochloride, organochlorine compound, chlorocarbon, or chlorinated hydrocarbon is an organic compound containing at least one covalently bonded atom of chlorine that has an effect on the chemical behavior of the molecule. The chloroalkane class (alkanes with one or more hydrogens substituted by chlorine) provides common examples. The wide structural variety and divergent chemical properties of organochlorides lead to a broad range of names and applications. Organochlorides are very useful compounds in many applications, but some are of profound environmental concern.
Physical and chemical properties.
Chlorination modifies the physical properties of hydrocarbons in several ways. The compounds are typically denser than water due to the higher atomic weight of chlorine versus hydrogen. Aliphatic organochlorides are alkylating agents because chloride is a good leaving group.
Natural occurrence.
Many organochlorine compounds have been isolated from natural sources ranging from bacteria to humans. Chlorinated organic compounds are found in nearly every class of biomolecules including alkaloids, terpenes, amino acids, flavonoids, steroids, and fatty acids. Organochlorides, including dioxins, are produced in the high temperature environment of forest fires, and dioxins have been found in the preserved ashes of lightning-ignited fires that predate synthetic dioxins. In addition, a variety of simple chlorinated hydrocarbons including dichloromethane, chloroform, and carbon tetrachloride have been isolated from marine algae. A majority of the chloromethane in the environment is produced naturally by biological decomposition, forest fires, and volcanoes.
The natural organochloride epibatidine, an alkaloid isolated from tree frogs, has potent analgesic effects and has stimulated research into new pain medication. However, because of its unacceptable therapeutic index, it is no longer being researched for potential therapeutic uses.
The frogs obtain epibatidine through their diet and then sequester it on their skin. Likely dietary sources are beetles, ants, mites, and flies.
Preparation.
From chlorine.
Alkanes and aryl alkanes may be chlorinated under free radical conditions, with UV light. However, the extent of chlorination is difficult to control. Aryl chlorides may be prepared by the Friedel-Crafts halogenation, using chlorine and a Lewis acid catalyst.
The haloform reaction, using chlorine and sodium hydroxide, is also able to generate alkyl halides from methyl ketones, and related compounds. Chloroform was formerly produced thus.
Chlorine adds to the multiple bonds on alkenes and alkynes as well, giving di- or tetra-chloro compounds.
Reaction with hydrogen chloride.
Alkenes react with hydrogen chloride (HCl) to give alkyl chlorides. For example, the industrial production of chloroethane proceeds by the reaction of ethylene with HCl:
In oxychlorination, hydrogen chloride instead of the more expensive chlorine for the same purpose:
Secondary and tertiary alcohols react with hydrogen chloride to give the corresponding chlorides. In the laboratory, the related reaction involving zinc chloride in concentrated hydrochloric acid:
Called the Lucas reagent, this mixture was once used in qualitative organic analysis for classifying alcohols.
Other chlorinating agents.
Alkyl chlorides are most easily prepared by treating alcohols with thionyl chloride (SOCl2) or phosphorus pentachloride (PCl5), but also commonly with sulfuryl chloride (SO2Cl2) and phosphorus trichloride (PCl3):
In the laboratory, thionyl chloride is especially convenient, because the byproducts are gaseous. Alternatively, the Appel reaction can be used:
Reactions.
Alkyl chlorides are versatile building blocks in organic chemistry. While alkyl bromides and iodides are more reactive, alkyl chlorides tend to be less expensive and more readily available. Alkyl chlorides readily undergo attack by nucleophiles.
Heating alkyl halides with sodium hydroxide or water gives alcohols. Reaction with alkoxides or aroxides give ethers in the Williamson ether synthesis; reaction with thiols give thioethers. Alkyl chlorides readily react with amines to give substituted amines. Alkyl chlorides are substituted by softer halides such as the iodide in the Finkelstein reaction. Reaction with other pseudohalides such as azide, cyanide, and thiocyanate are possible as well. In the presence of a strong base, alkyl chlorides undergo dehydrohalogenation to give alkenes or alkynes.
Alkyl chlorides react with magnesium to give Grignard reagents, transforming an electrophilic compound into a nucleophilic compound. The Wurtz reaction reductively couples two alkyl halides to couple with sodium.
Applications.
Vinyl chloride.
The largest application of organochlorine chemistry is the production of vinyl chloride. The annual production in 1985 was around 13 billion kilograms, almost all of which was converted into polyvinylchloride (PVC).
Chloromethanes.
Most low molecular weight chlorinated hydrocarbons such as chloroform, dichloromethane, dichloroethene, and trichloroethane are useful solvents. These solvents tend to be relatively non-polar; they are therefore immiscible with water and effective in cleaning applications such as degreasing and dry cleaning. Several billion kilograms of chlorinated methanes are produced annually, mainly by chlorination of methane:
The most important is dichloromethane, which is mainly used as a solvent. Chloromethane is a precursor to chlorosilanes and silicones. Historically significant, but smaller in scale is chloroform, mainly a precursor to chlorodifluoromethane (CHClF2) and tetrafluoroethene which is used in the manufacture of Teflon.
Pesticides.
The two main groups of organochlorine insecticides are the DDT-type compounds and the chlorinated alicyclics.
Their mechanism of action differs slightly.
Insulators.
Polychlorinated biphenyls (PCBs) were once commonly used electrical insulators and heat transfer agents. Their use has generally been phased out due to health concerns. PCBs were replaced by polybrominated diphenyl ethers (PBDEs), which bring similar toxicity and bioaccumulation concerns.
Toxicity.
Some types of organochlorides have significant toxicity to plants or animals, including humans. Dioxins, produced when organic matter is burned in the presence of chlorine, are persistent organic pollutants which pose dangers when they are released into the environment, as are some insecticides (such as DDT). For example, DDT, which was widely used to control insects in the mid-20th century, also accumulates in food chains, as do its metabolites DDE and DDD, and causes reproductive problems (e.g., eggshell thinning) in certain bird species. DDT also posed further issues to the environment as it is extremely mobile, traces even being found in Antarctica despite the chemical never being used there. Some organochlorine compounds, such as sulfur mustards, nitrogen mustards, and Lewisite, are even used as chemical weapons due to their toxicity.
However, the presence of chlorine in an organic compound does not ensure toxicity. Some organochlorides are considered safe enough for consumption in foods and medicines. For example, peas and broad beans contain the natural chlorinated plant hormone 4-chloroindole-3-acetic acid (4-Cl-IAA); and the sweetener sucralose (Splenda) is widely used in diet products. , at least 165 organochlorides had been approved worldwide for use as pharmaceutical drugs, including the natural antibiotic vancomycin, the antihistamine loratadine (Claritin), the antidepressant sertraline (Zoloft), the anti-epileptic lamotrigine (Lamictal), and the inhalation anesthetic isoflurane.
Rachel Carson brought the issue of DDT pesticide toxicity to public awareness with her 1962 book "Silent Spring". While many countries have phased out the use of some types of organochlorides such as the US ban on DDT, persistent DDT, PCBs, and other organochloride residues continue to be found in humans and mammals across the planet many years after production and use have been limited. In Arctic areas, particularly high levels are found in marine mammals. These chemicals concentrate in mammals, and are even found in human breast milk. In some species of marine mammals, particularly those that produce milk with a high fat content, males typically have far higher levels, as females reduce their concentration by transfer to their offspring through lactation.


Yttrium(III) phosphate

 Yttrium phosphate, YPO4, is the phosphate salt of yttrium. It occurs in nature as mineral xenotime.


Gallane

Gallane, also systematically named trihydridogallium, is an inorganic compound of gallium with the chemical formula (also written as ). It is a photosensitive, colourless gas that cannot be concentrated in pure form. Gallane is both the simplest member of the gallanes, and the prototype of the monogallanes. It has no economic uses, and is only intentionally produced for academic reasons.
It has been detected as a transient species in the gas phase; also at low temperature (3.5 K) following the reaction of laser ablated gallium atoms and dihydrogen, and more recently in an argon matrix doped with vapour over solid digallane, Ga2H6.
Structure of monomeric GaH3.
I.R spectroscopic studies indicate that monomeric GaH3 has a trigonal planar structure. Theoretical Ga-H bond lengths have been calculated as being in the range 155.7 pm to 158.7 pm.
Monomeric GaH3 dimerises in the vapor phase to form Ga2H6, digallane(6) and the enthalpy change associated with the gas phase dissociation reaction Ga2H6 → 2GaH3 has been experimentally estimated as 59 ± 16 kJ mol−1.
Chemical properties.
As GaH3 cannot be prepared or isolated readily reactions involving GaH3 either use the dimer, Ga2H6, digallane(6) or adducts of GaH3 for example L·GaH3 where L is a monodentate ligand.
GaH3 adducts.
The production of adducts can proceed via the direct reaction of digallane(6) or more often due to the thermal fragility of digallane(6) (which decomposes to gallium metal and hydrogen above -20 °C) using a tetrahydridogallate salt as a starting point (e.g. LiGaH4) or alternatively via ligand displacement from an existing adduct.
Examples are:
Many adducts have been prepared. There are a number of typical structures with neutral adducts (L = monodentate ligand, L-L is bidentate):
In comparison to alane (AlH3) with similar ligands, gallane tends to adopt lower coordination numbers. Also whilst N donor ligands form stronger bonds to alumane than phosphines the reverse is typically true for gallane.
The monomeric structure of Me3N.GaH3 has been confirmed in both the gas and solid phases. In this regard, the 1:1 adduct contrasts with the corresponding alane complex, Me3N.AlH3 which in the solid is dimeric with bridging hydrogen atoms.
Solute properties.
Gaseous gallane is a hydrophilic (non-polar) aprotic solute. It dissolves in polar compounds such as tetramethylethylenediamine, from which it can be crystallised as gallane—N,N,N′,N′-tetramethylethane-1,2-diamine (1/1).
Other chemical reactions.
Upon treatment with a standard base, it converts to a metal tetrahydroxygallanuide (the anion Ga(OH)4−) and hydrogen gas.
With strong bases, it can be deprotonated to give .
Reduction of gallane gives gallium metal. Upon treatment with a standard acid, it converts to a gallium(3+) salt and hydrogen gas. Oxidation of gallane gives Ga(OH)3, gallium(III) hydroxide.
Unsolvated gallane is in chemical equilibrium with digallane(6), being the dominant species with increasing temperature. Due to this equilibrium, gallane and digallane(6) are often considered to be chemically equivalent. Reactions requiring gallane as opposed to digallane(6), must be carried out in solution. Common solvents include tetrahydrofuran, and diethyl ether.


Graphenated carbon nanotube

Graphenated carbon nanotubes are a relatively new hybrid that combines graphitic foliates grown along the sidewalls of multiwalled or bamboo style carbon nanotubes (CNTs). Yu "et al." reported on "chemically bonded graphene leaves" growing along the sidewalls of CNTs. Stoner "et al." described these structures as "graphenated CNTs" and reported in their use for enhanced supercapacitor performance. Hsu "et al." further reported on similar structures formed on carbon fiber paper, also for use in supercapacitor applications. Pham "et al." also reported a similar structure, namely "graphene-carbon nanotube hybrids", grown directly onto carbon fiber paper to form an integrated, binder free, high surface area conductive catalyst support for Proton Exchange Membrane Fuel Cells electrode applications with enhanced performance and durability. The foliate density can vary as a function of deposition conditions (e.g. temperature and time) with their structure ranging from few layers of graphene (< 10) to thicker, more graphite-like.
The fundamental advantage of an integrated graphene-CNT structure is the high surface area three-dimensional framework of the CNTs coupled with the high edge density of graphene. Graphene edges provide significantly higher charge density and reactivity than the basal plane, but they are difficult to arrange in a three-dimensional, high volume-density geometry. CNTs are readily aligned in a high density geometry (i.e., a vertically aligned forest) but lack high charge density surfaces—the sidewalls of the CNTs are similar to the basal plane of graphene and exhibit low charge density except where edge defects exist. Depositing a high density of graphene foliates along the length of aligned CNTs can significantly increase the total charge capacity per unit of nominal area as compared to other carbon nanostructures.


Silanol

A silanol is a functional group in silicon chemistry with the connectivity Si–O–H. It is related to the hydroxy functional group (C–O–H) found in all alcohols. Silanols are often invoked as intermediates in organosilicon chemistry and silicate mineralogy. If a silanol contains one or more organic residue, it is an organosilanol.
Preparation.
From alkoxysilanes.
The first isolated example of a silanol was Et3SiOH, reported in 1871 by Albert Ladenburg. He prepared the “silicol” by hydrolysis of Et3SiOEt (Et = C2H5).
From silyl halides and related compounds.
Silanols are generally synthesized by hydrolysis of halosilanes, alkoxysilanes, or aminosilanes. Chlorosilanes are the most common reactants:
The hydrolysis of fluorosilanes requires more forcing reagents, i.e. alkali. The alkoxysilanes (silyl ethers) of the type R3Si(OR') are slow to hydrolyze. Compared to the silyl ethers, silyl acetates are faster to hydrolyze, with the advantage that the released acetic acid is less aggressive. For this reason silyl acetates are sometimes recommended for applications.
By oxidation of silyl hydrides.
An alternative route involves oxidation of hydrosilanes. A wide range of oxidants have been employed including air, peracids, dioxiranes, and potassium permanganate (for hindered silanes). In the presence of metal catalysts, silanes undergo hydrolysis:
Structure and examples.
The Si–O bond distance is typically about 1.65 Å. In the solid state, silanols engage in hydrogen-bonding.
Most silanols have only one OH group, e.g. trimethylsilanol. Also known are some silanediols, e.g., diphenylsilanediol. For sterically bulky substituents, even silanetriols have been prepared.
Reactions.
Acidity.
Silanols are more acidic than the corresponding alcohols. This trend contrasts with the fact that Si is far less electronegative than carbon (1.90 vs 2.55, respectively). For Et3SiOH, the p"K"a is estimated at 13.6 vs. 19 for "tert"-butyl alcohol. The p"K"a of (3-ClC6H4)Si(CH3)2OH is 11. Because of their greater acidity, silanols can be fully deprotonated in aqueous solution, especially the arylsilanols. The conjugate base is called a siloxide or a silanolate.
Despite the disparity in acidity, the basicities of alkoxides and siloxides are similar.
Condensation and the sol-gel process.
Silanols condense to give disiloxanes:
The conversions of silyl halides, acetates, and ethers to siloxanes proceed via silanols. The sol-gel process, which entails the conversion of, for example, Si(OEt)4 into hydrated SiO2, proceeds via silanol intermediates.
Occurrence.
Silanols exist not only as chemical compounds, but are pervasive on the surface of silica and related silicates. Their presence is responsible for the absorption properties of silica gel. In chromatography, derivatization of accessible silanol groups in a bonded stationary phase with trimethylsilyl groups is referred to as endcapping. Organosilanols occur as intermediates in industrial processes such as the manufacturing of silicones. Moreover, organosilanols occur as metabolites in the biodegradation of small ring silicones in mammals.
Biorelevance.
Some silanediols and silanetriols inhibit hydrolytic enzymes such as thermolysin and acetycholinesterase.
Parent silanols.
Literally, silanol refers to a single compound with the formula H3SiOH (Chemical Abstracts number 14475-38-8). The family SiH4−"n"(OH)"n" ("n" = 1, 2, 3, 4) are highly unstable and are mainly of interest to theoretical chemists. The perhydroxylated silanol, sometimes called orthosilicic acid, is often discussed in vague terms, but has not been well characterized.


Carmofur

Carmofur (INN) or HCFU (1-hexylcarbamoyl-5-fluorouracil) is a pyrimidine analogue used as an antineoplastic agent. It is a derivative of fluorouracil, being a lypophilic-masked analog of 5-FU that can be administered orally.
Biology.
Carmofur prodrug is ingested and taken up in the intestine, overcoming the problem of 5-FU degradation by dihydropyrimidine dehydrogenase. Once inside a cell, carmofur prodrug is converted into 5-FU.
Mechanism of action.
The mechanism of action of carmofur prodrug is traditionally thought to be the generation of 5–FU. However, carmofur is a highly potent acid ceramidase (AC) inhibitor. Ceramide influences cancer cell survival, growth and death. Inhibition of AC activity sensitizes tumor cells to the effects of antineoplastic agents and radiation. Carmofur, much more effective than temozolomide, has been reported as the small-molecule drug capable of killing adult and pediatric glioblastomas.
Medicinal uses.
Product marketing for carmofur started in 1981. Carmofur has also been used as adjuvant chemotherapy for curatively resected colorectal cancer patients in China, Japan, and Finland for many years. Trials and meta-analyses have confirmed that the drug is effective on patients with this cancer type, extending their survival.
Carmofur has been shown to inhibit the SARS-CoV-2 main protease, and is therefore a promising lead compound to develop new antiviral treatment for COVID-19.
Adverse effects.
As fluorouracil, carmofur has been known to induce leukoencephalopathy, characterized by progressive damage to white matter in the brain with stroke-like symptoms.
A clinical trial for small hepatocellular carcinoma was stopped prematurely because 56% of the treated patients had unacceptable side effects. Moreover, the treatment had no survival advantage for stage 1 and 2 cancer patients. This may be a reason why carmofur was never pursued for FDA-approval in the US.
Chemical synthesis.
Ozaki et al. has reported carmofur synthesized by treating 5-FU with phosgene and hexylamine. Xiong et al. reported an alternative approach for carmofur synthesis. Chemical preparations and structures can be found here.


Monopotassium arsenate

Monopotassium arsenate is the inorganic compound with the formula KH2AsO4. A white solid, this salt is used to prepared other arsenic-containing compounds, mainly pesticides. It is prepared by calcining arsenic oxide and potassium nitrate, followed by extraction with water.
Relevant acid-base equilibria for aqueous solutions of this diprotic acid derived from arsenic acid are as follows:


Silver permanganate

Silver permanganate is an inorganic compound with the chemical formula AgMnO4. This salt is a purple crystal adopting monoclinic crystal system. It decomposes when heated or mixed with water, and heating to high temperature may lead to explosion. The compound is used in gas masks.
Production.
It can be produced through the reaction of silver nitrate and potassium permanganate:


Ammonium fluorosilicate

Ammonium fluorosilicate (also known as ammonium hexafluorosilicate, ammonium fluosilicate or ammonium silicofluoride) has the formula (NH4)2SiF6. It is a toxic chemical, like all salts of fluorosilicic acid. It is made of white crystals, which have at least three polymorphs and appears in nature as rare minerals cryptohalite or bararite.
Structure.
Ammonium fluorosilicate has three major polymorphs: α-(NH4)2[SiF6] form is cubic (space group Fm3m, No. 225) and corresponds to the mineral cryptohalite. The β form is trigonal (scalenohedral) and occurs in nature as mineral bararite. A third (γ) form was discovered in 2001 and identified with the hexagonal 6mm symmetry. In all three configurations, the [SiF6]2− octahedra are arranged in layers. In the α form, these layers are perpendicular to [111] directions. In the β- and γ- forms, the layers are perpendicular to the c-axis. (Note: trigonal symmetry is part of the hexagonal group, but not all hexagonal crystals are trigonal.) The silicon atoms of α-(NH4)2[SiF6] (alpha), have cubic close packing (CCP). The γ form has hexagonal close packing and the β-(NH4)2[SiF6] has primitive hexagonal packing. In all three phases, 12 fluorine atoms neighbor the (NH4)+.
Although bararite was claimed to be metastable at room temperature, it does not appear one polymorph has ever turned into another. Still, bararite is fragile enough that grinding it for spectroscopy will produce a little cryptohalite. Even so, ammonium fluorosilicate assumes a trigonal form at pressures of 0.2 to 0.3 GPa. The reaction is irreversible. If it is not bararite, the phase is at least very closely related.
The hydrogen bonding in (NH4)2[SiF6] allows this salt to change phases in ways that normal salts cannot. Interactions between cations and anions are especially important in how ammonium salts change phase. (To learn more about the β-structure, see Bararite.)
Natural occurrence.
This chemical makes rare appearances in nature. It is found as a sublimation product of fumaroles and coal fires. As a mineral, it is either called cryptohalite or bararite, the two being two polymorphs of the compound.
Chemical properties and health hazards.
Ammonium fluorosilicate is noncombustible, but it will still release dangerous fumes in a fire, including hydrogen fluoride, silicon tetrafluoride, and nitrogen oxides. It will corrode aluminium. In water, ammonium fluorosilicate dissolves to form an acid solution.
Inhaling dust can lead to pulmonary irritation, possibly death. Ingestion may also prove fatal. Irritation of the eyes comes from contact with the dust, as well as irritation or ulceration of the skin.
Uses.
Ammonium fluorosilicate finds use as a disinfectant, and it is useful in etching glass, metal casting, and electroplating. It is also used to help neutralize washing machine water as laundry sour.


Manganese monosilicide

Manganese monosilicide (MnSi) is an intermetallic compound, a silicide of manganese. It occurs in cosmic dust as the mineral brownleeite. MnSi has a cubic crystal lattice with no inversion center; therefore its crystal structure is helical, with right-hand and left-hand chiralities.
MnSi is a paramagnetic metal that turns into a ferromagnet at cryogenic temperatures below 29 K. In the ferromagnetic state, the spatial arrangement of electron spins in MnSi changes with magnetic field, forming helical, conical, skyrmion, and regular ferromagnetic phases.
Crystal structure and magnetism.

Giorgio Coricelli

Giorgio Coricelli is professor of economics and psychology at the University of Southern California, specializing in neuroeconomics. Having done his undergraduate studies at La Sapienza in Rome, he then completed his Ph.D. at the Economic Science Laboratory of the University of Arizona studying with Vernon Smith, shortly before Smith received his Nobel Prize in economics in 2002.
His research focuses on neuroeconomics, experimental economics and game theory. Besides Vernon Smith, he collaborated with Kevin McCabe, Aldo Rustichini and Sarah-Jayne Blakemore. He founded the Neuroeconomics Lab at USC, while being a member of the CNRS and of the CIMEC lab in Trento, Italy.
Research.
Coricelli was trained by the founding father of experimental economics, Vernon Smith, and later joined in 2004 the Institut des Sciences Cognitives in Lyon, France, to perform experimental research using neuroimaging. His work combines economics with scientific psychology, and aims at "understanding human behaviors emerging from the interplay of cognitive and emotional systems" in the human mind, more specifically "the role of emotions in decision-making and the relational complexity in social interaction".
His most cited work investigated counterfactual thinking and its locus of activity in the brain, in particular for the emotion of regret. Using game theory and in collaboration with Rosemarie Nagel, he also investigated strategic thinking and identified the brain loci of different levels of strategic reasoning (in beauty contest games). His most recent work has focused on bounded rationality, social uncertainty, social learning, and impaired decision-making. Among his influences are William James and Piero Sraffa. He coined the term "neuroeconomics" while working at Vernon Smith's lab in Arizona.


Archives of Physical Medicine and Rehabilitation

The Archives of Physical Medicine and Rehabilitation is the official journal of the American Congress of Rehabilitation Medicine (ACRM). The journal is published monthly by Elsevier and is the most highly cited journal in the Rehabilitation category of the Thomson Reuters Journal Citation Reports. The 2018 Impact Factor was 2.697.
In addition to the original research, reviews, and commentary submitted to the journal, The Archives publishes the abstracts to the ACRM Annual Conference each year. The ACRM is an organization of rehabilitation professionals dedicated to serving people with disabling conditions by supporting research that promotes health, independence, productivity, and quality of life; and meets the needs of rehabilitation clinicians and people with disabilities. ACRM's current President is Pamela Roberts. ACRM's CEO is Jon Lindberg.
The journal is edited by Leighton Chan and Allen W. Heinemann. The Deputy Editor is Helen Hoenig.
Awards.
Sidney Licht was a longtime member of the American Congress of Rehabilitation Medicine and was its president in 1967–68. He was the editor of the "Physical Medicine Library", which was published by his wife, Elizabeth. The Licht award originated in March 1979 with its first award presented to Carl Granger, Gary Albrecht, and Byron Hamilton for their article "Outcomes of Comprehensive Medical Rehabilitation: Measurement by PULSES Profile and the Barthel Index". The award is given every year for the best scientific article published in "Archives of Physical Medicine and Rehabilitation" during the previous year.
Abstracting and indexing.
The contents of "Archives of Physical Medicine and Rehabilitation" are indexed in Index Medicus/MEDLINE, Excerpta Medica/EMBASE, Current Contents/Clinical Medicine, Science Citation Index, Citation alert, BIOSIS Previews, and CINAHL.


Clarissa Caldwell Lathrop

Clarissa Caldwell Lathrop (1847 – September 11, 1892) was an American social reformer and autobiographer. Her prominence came from her remarkable experience, being confined and unlawfully imprisoned in the Utica Lunatic Asylum for 26 months (October 1880 – December 1882), through a plot of a secret enemy to kill her. She eventually managed to communicate with James Bailey Silkman, a lawyer who, like herself, was confined in the same asylum under similar circumstances. He succeeded in obtaining a writ of "habeas corpus", and Judge George G. Barnard of the New York Supreme Court pronounced Lathrop sane and unlawfully incarcerated.
After that time, she devoted her life to ameliorating the laws relating to lunacy. Lathrop felt she owed it to women to take her case before the New York State Legislature, and demand reform in this direction, but she was unsuccessful in two efforts and found herself penniless and facing the need to support herself. After several efforts, she became a court stenographer, and ten years after her release, wrote a book, the story of her own institutionalization, entitled "A Secret Institution." Published at her own expense, this book led to the formation of the Lunacy Law Reform League, in 1889, a national organization with headquarters in New York City, of which Lathrop became the secretary and was the national organizer.
Early years and education.
Clarissa Caldwell Lathrop was born in Rochester, New York. She was a daughter of Gen. William E. Lathrop, a Brigadier General of the National Guard. Lathrop's father had met and married Lathrop's mother, Jemima, at the age of 42 – Jemima was 19. Lathrop had been one of five children, but had lost her eldest brother to disease in 1865 and her second eldest brother moved to the southern part of the country to look for work. Lathrop's father passed away in 1877 leaving his wife, and his three daughters to open their home to board strangers for income.
She graduated from the Rochester Academy.
Lathrop also often traveled significant distances and visited friends around Rochester.
Career.
Teacher.
Lathrop became a teacher, which, owing to her father's failure in business, became a means of support to her family as well as to herself. She continued to teach successfully until her unlawful imprisonment in the Utica State Hospital (formerly known as the New York State Lunatic Asylum at Utica).
Utica Lunatic Asylum incarceration and release.
Lathrop feared that Miss Hamlo, a boarder in her mother's house, was poisoning her. Lathrop was obsessed with a Mr. Zell, a former lover who married another woman after Lathrop rejected him. After repenting her decision to reject Zell, Lathrop became convinced that Hamlo was in alliance with Zell's wife. After Lathrop began seeing Zell everywhere, she believed he had divorced, and would now marry her if Lathrop survived Hamlo's poisonings. When Lathrop's life was saved on two occasions by friends, she took some of the aconite-poisoned tea to a chemist for analysis, as she sought reliable proof before making open charges against any one. At the instigation of a doctor who was in sympathy with the plot to incarcerate Lathrop, she went to Utica to consult Dr. John P. Gray, Superintendent of the State Lunatic Asylum in Utica, New York. Instead of seeing Grey, upon her arrival, she was incarcerated with the insane, without the commitment papers required by law, and kept a prisoner at the asylum for 26 months.
She was sent to the asylum at the insistence of her mother and sisters, who lived in Rochester, and who asserted that Lathrop was suffering from the delusion that somebody was trying to poison her. Her answer was that it was not a delusion, that somebody was endeavoring to poison her. But she was willing to accept proof to the contrary, which was also evidence that there was no delusion. Nonetheless, her incarceration ensued. By the time Lathrop was admitted to the asylum, she was 32 years old and unmarried despite engagements to two different men. Her first engagement was broken off by her fiancé due to cold feet and her second betrothed died from consumption.
The hospital, according to Lathrop was “a living tomb.”
Within a few weeks of her arrival at Utica, Lathrop had written letters to two of her physician friends only to find out later that her letters had never been mailed. The attending physician claimed they were not sent because the asylum was not obliged to send her letters “all over the country.” Lathrop was “amazed and dumbfounded” at the idea that not only would her letters be read by the asylum doctors, but that they would never reach their intended destination. Lathrop had easily made a friend who had revealed to her how she would be able to communicate to the outside world without getting caught by the authorities. She obtained paper through another patient who had hidden the contraband in her room. The woman would not out rightly give the paper to Lathrop for fear of punishment for aiding and abetting, but hinted that there was nothing she could do if Lathrop took a page or two while she was elsewhere. Lathrop also wrote on newspaper edges and scraps of wrapping paper which she also hid in her skirt.
Eventually, she managed to communicate with Silkman, a New York lawyer, who had been forcibly carried off and imprisoned in the same insane asylum. He obtained a writ of "habeas corpus" at once on behalf of Lathrop, and in December, 1882, Judge Barnard of the New York Supreme Court pronounced Lathrop to be sane and unlawfully incarcerated.
Social reformer and autobiographer.
Immediately upon her release, Lathrop went before the New York State Legislature. She described her experience and the necessity for reform. After making another fruitless effort the succeeding year, she found herself homeless and penniless, and dependent upon a cousin's generosity for shelter and support, forced to begin her new life under the most difficult circumstances.
Lathrop collected money for a charitable society on a commission, spending her evenings studying stenography and typewriting. She soon started a business of her own and was successful as a court stenographer. Ten years after her release, she wrote her book, "A Secret Institution", which was a history of her own life, written in the style of a novel, and descriptive of what she experienced or witnessed while an inmate of the Utica asylum.
Keeping true to her vow “to devote the rest of [her] life to the cause of the insane,” Lathrop formed the Lunacy Law Reform and the Anti-Kidnapping Leagues. The Leagues provided legal services to asylum patients who felt they were victims of a corrupt legal system. The goal of the leagues was to “protect sane people from false imprisonment.” Both groups had helped several individuals who had been unjustly incarcerated secure their freedom. The Lunacy Law Reform League in 1889, was a national organization having its headquarters in New York City, of which she was secretary and national organizer.
 Lathrop spoke out against asylum abuses, and became a spokesperson for others incarcerated as insane. She lived with self-doubt, fear, and suspicion, while trying to understand how incarceration affected her. She struggled with society's perceptions of her mental stability.
Lathrop died in Saratoga, New York, on September 11, 1892, and is buried at Mount Hope Cemetery, in Rochester.
Legal case.
Albert Bach, legal counsel to Lathrop, held that the interesting point in the case was the question of the deprivation of Lathrop's postal rights while in the asylum. She was not permitted to have writing materials, and even though she succeeded in obtaining them, the asylum authorities disposed of her letters as they pleased. The claim was asserted that asylum managers have no such control over inmates as have prison managers; that the former institutions have more of the character of hospitals. Bach found nothing in the by-laws of the Utica asylum giving the right to this close supervision. He said that there were many instances of wrongful incarceration, and that justice would seem to dictate that inmates of asylums should have access to the mails. Even though much of it would be trash, it would be well worth while to endure that if information could be obtained to the release of a person improperly detained.
Reports suggested that Lathrop would bring a suit of U$25,000 damages against the management of the Utica State Insane Asylum. The grounds alleged were the wrongful detention of herself, and the seizure of her letters written to friends asking them to help her to regain her liberty. Lathrop's lawyer gave the following statement of the scope of the lawsuit: Of course the main point is in regard to the interception of letters that she wrote to friends asking for assistance. If the managers of the asylums have the right to intercept letters, they have the power to shut a person entirely from the world, whether the person be insane or not. This is a difference between a criminal and a lunatic. In the case of a criminal he is in his position through his own fault, but the insane person is a patient, and deserves all possible consideration. If they stop a person’s letters, they virtually remove from that person the possibility of obtaining release. The suit is brought not so much for the sake of damages, as to test the point whether or not the managers of asylums have a right to enforce such a rule. I have become interested in the matter, and intend to follow it up and test the question thoroughly. One of the things I will do will be to write to the Postmaster General, asking if it would not be advisable in case we can prove that the authorities are wrong in prohibiting the forwarding of letters, to place free delivery boxes in all asylums, that the patients may have a chance to correspond without difficulty with their friends. I believe such a system would do away with much of the abuse that without doubt exists in many asylums, and would greatly lessen the chance of sane persons being held in confinement.


25th Station Hospital Unit

The 25th Station Hospital was an all African American unit of nurses who served in the Army Nurse Corps during World War II. The unit was the first African American group sent overseas and were stationed for a short tour in Liberia in 1943.
About.
The 25th Station Hospital was the first United States Army medical unit of African American service members to deploy overseas during World War II. These nurses from the Army Nurse Corps were sent to Liberia in March of 1943. There were 30 nurses in the unit and they were there to support United States troops on airfields and rubber plantations. The group's chief nurse was First Lieutenant Susan E. Freeman and they were stationed on Roberts Field. Most of the soldiers they tended suffered from malaria.
The nurses did not carry weapons and to show this, they all wore Red Cross arm bands. They were also issued helmets, gas masks and canteens. The work that the nurses were asked to do was duplicated by Army corpsmen and morale among the nurses' unit suffered. The same year they were deployed, the 25th Station Hospital Unit was recalled because of the morale issue and poor health in the unit.
In April of 1944, official from Liberia requested and were granted permission to honor Lieutenant Freeman with the Liberian Human Order of African Redemption. She was also awarded a Mary Mahoney Award from the National Association of Colored Graduate Nurses in 1944 for her work in Liberia.


Nanocluster


Robert Herring (businessman)

Robert S. Herring, Sr. (born September 22, 1941) is an American businessman who founded Herring Networks, a media company that launched and currently owns AWE and One America News Network.
Early life.
Herring was born in Marksville, Louisiana, the son of a share-cropper. The family moved to California in 1948. After his father died, he dropped out of high school at age 14 and worked to support his family. In 1964, he founded a small chain of pet shops in Los Angeles County, California.
Career.
In 1972, he founded Industrial Circuits, which he sold to Toppan Printing in 1988. He was the founder and owner of Herco Technology before selling the company to Teradyne in 2000
In 2003, Herring founded Herring Networks, a media network based in San Diego. In 2013, the network launched One America News Network, a news organization known for conservative news coverage.
In 2005, Herring offered $1 million to the husband in the Terri Schiavo case for the husband to cede custody of Terri to Terri's parents.


Camp Discovery

Camp Discovery is a therapedic summer camp located at Gainesboro, Tennessee (between Nashville and Knoxville) for Tennessee-area children and adults with disabilities such as muscular dystrophy, cancer, cerebral palsy, Down syndrome, as well as various developmental disabilities.
It has been in operation since 1983 and it was founded and still operated by the Tennessee Jaycee Foundation.
Background.
In 1971, the ARC asked the Jaycees to open a Foster Grandparent Program. Two years later, the ARC returned and asked to start another program for the mentally challenged, afterwards the Tennessee Jaycees Foundation was established in 1977 with John Germ as president. Less than a year later, a permanent camp site selection began for Camp Jaycee (renamed Camp Discovery in 1982 to avoid confusion). An application was made in 1980 and a lease was granted a year later to begin construction, then in 1983, the camp officially opens and the first 125 campers arrived. Many additions such as the dining hall, log cabins, and amphitheaters further enhanced the effectiveness of this camp.