osmium (os'me-um)

A metallic element, a ociated in nature with platinum and iridium. The metal is used for incandescent electric lamps. Its salt, OsGi, is used as a stain. Symbol, Os; atomic weight, 191. It is the heaviest body known, having a specific gravity. of 22.477. o. amid. An orange yellow, odorle , crystalline powder, OSO2NH2, discovered by Fremy. It colors all animal ti ues at first brown and subsequently black. It has been recommended in place of osmic acid for histological research. o. tetroxid. OsCu, the an hydrid of the theoretical osmic acid. It has been used by intra neural injection to produce degeneration of nerves in persistent neuralgia. It is to be avoided in renal disease. Locally applied, it acts as a caustic. It has the property of staining fatty matters black, and is used as a reagent in microscopy for this purpose. [Gr., osme, an odor.]