tungsten

[Sw. tungsten =heavy stone; Ger. schwerstein.] 1. Chem.: Wolfram. A hexad metallic element, symbol, W; atomic weight, 184; specific gravity, 17.4; found as ferrous tungstate in the mineral wolfram, and obtained as a dark-gray powder by strongly heating tungstic oxide in a stream of hydrogen. It is a white, nearly infusible metal, very hard and brittle, unaffected by air or by water at the ordinary temperature, insoluble in hydrochloric and dilute sulphuric acids, but oxidized by concentrated sulphuric acid, and by nitric acid. It forms two cla es of compounds, in which it is quadrivalent and sexvalent respectively. 2. Min.: The same as SCHEELITE (q. v.).