Rearrangements wonât occur if the initially formed carbocation is the most thermodynamically stable out of all the possible isomers. For example, if you use t-butyl bromide in a Friedel-Crafts alkylation, it will not rearrange, since the t-butyl c... This page may be out of date. Save your draft before refreshing this page.
Platinum was first used for minting coins in Spanish-colonized America. Following the discovery of platinum in gold rocks, the Spaniards were unable to use it for a long time because they had no technology for processing this metal.latinum was first used for minting coins in Spanish-colonized America. Following the discovery of platinum in gold rocks, the Spaniards were unable to use it for a long time because they had no technology for processing this metal.
Iridium and osmium were identified in the black residue remaining after dissolving platinum ore with aqua regia, a mixture of 25% nitric acid (HNO 3) and 75% hydrochloric acid (HCl). Today, iridium is still obtained from platinum ores and as a by-product of mining nickel.Pure iridium is very brittle and is nearly impossible to machine. It is primarily used as a hardening agent for platinum.Platinum-iridium alloys are used to make crucibles and other high temperature equipment. Iridium is also alloyed with osmium to make the tips of fountain pens and compass bearings.Iridium is the most corrosive resistant metal known.ure iridium is very brittle and is nearly impossible to machine. It is primarily used as a hardening agent for platinum. Platinum-iridium alloys are used to make crucibles and other high temperature equipment.