Period 6 element heavy metal, lead is a neurotoxin that accumulates both in soft tissues and the bones. Lead poisoning has been documented from ancient Rome, ancient Greece, and ancient China. Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent other metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery white color when newly made, but often seen in air with a pink tinge owing to the surface
Crystal structure of boron-rich metal borides p-type electrical conductivity. Increasing the conductivity is a key issue for thermoelectric applications of these borides. YB is used as a soft-X-ray monochromator for dispersing 1–2 keV synchrotron radiation at some synchrotron radiation facilities. Contrary to thermoelectric applications, high thermal conductivity is desirable for synchrotron radiation monochromators. YB exhibits low, amorphous-like thermal conductivity. However, transition metal doping increases the thermal conductivity twice in YNbB as compared to undoped YB. Crystal structure of boron-rich metal borides Metals, and specifically rare-earth elements, form numerous chemical complexes with boron. Their crystal structure and chemical bonding depend strongly on the metal element M and