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 This page may be out of date.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.
Early occurrences. Although the modern history of platinum only begins in the 18th century, platinum has been found in objects dating from 700 BC, in particular the famous Casket of Thebes (see image). This little box is decorated with hieroglyphics in gold, silver and an alloy of the platinum group metals.etween the end of the First World War and the 1950s, Canada was the world's major source of supply. In 1924 a farmer in the Transvaal province of South Africa discovered several nuggets of platinum in a riverbed.