Iridium

Iridium was discovered and named by a British scientist, Smithson Tennant. About 1800 he began an extended association with W. H. Wollaston in London for the purpose of improving the technology of the fabrication of platinum. This metal had for some time been known to dissolve almost completely in aqua regia, but a small black residue always remained and was for a time thought to be graphite.In the summer of 1803 Tennant began a study of this material which ultimately resulted in the identification of both osmium and iridium Almost simultaneously in France, L. N. Vauquelin and A. F. de Fourcroy, in Paris were working on the black residue left after three successive extractions of native platinum with aqua regia and proposed the existence of a new element. These observations were complemented by H.V. Collet-Descotiles. There can be no question that Tennant’s work owed much to the French research but he displayed greater insight than the latter.Iridium is a precious metal. It’s the densest element known and has the highest corrosion resistance. Its mechanical is notable such as its elasticity (the second, after osmium). Iridium is hard, fragile and can be easily worked between 1200 oC and 1500 oC.