A precious metal. Osmium is used in ball pens, as a forensic stain, and in electronic applications. Discovered in 1804 by Englishman Smithson Tennent in the residue left by dissolving platinum in aqua regia.
Powdered osmium is oxidized in air at room temperature to form highly toxic osmium tetroxide.
Found naturally with iridium , paladium , rhodium and platinum . Due to the high cost of osmium, there is none in our lab. The oxide is mildly acidic. Crystal are hexagonal. Click mass number for decay process, product for element page.