Discovery of osmium

Osmium was discovered in 1804 by the English chemist Smithson Tennant in London, in the same black residue from crude platinum in which he had already found iridium. He gave it a name taken from the Greek osme, meaning smell, since its volatile oxide has a sharp, unpleasant odour. Osmium is the densest naturally occurring element, about twice as dense as lead, and it is also very hard and brittle, with a bluish-white colour. Its tetroxide is toxic, so the metal is handled with care. It is mostly found in alloys with other platinum-group metals, which are used for fountain-pen nibs, electrical contacts and instrument pivots, where extreme hardness and resistance to wear are valuable.

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