Iridium was discovered in 1803 by Smithson Tennant in London when he used platinum ores and washed them with hydrochloric and nitric acid. Iridium is named after the Latin word ‘iris’ meaning colourful as its salts are highly coloured. It is hypothesised that the comet that struck the earth killing the dinosaurs was made of Iridium due to the rich Iridium layer located at the site of many impact sites. Iridium’s main use is in the hardening of platinum alloys and also making crucibles for heating due to its high melting point. It is a solid metal at room temperature with a melting point of 2466°c and a boiling point of 4130°c.
S.Tenant, A.F.Fourcory, L.N.Vauquelin, H.V.Collet-Descoltils