a very hard inert yellowish-white transition element that is the most corrosion-resistant metal known. It occurs in platinum ores and is used as an alloy with platinum. Symbol: Ir; atomic no: 77; atomic wt: 192.22; valency: 3 or 4; relative density: 22.42; melting pt: 2447°C; boiling pt: 4428°C
Word origin
C19: New Latin, from irido- + -ium; from its colourful appearance when dissolving in certain acids
iridium in American English
(aɪˈrɪdiəm; ɪˈrɪdiəm)
noun
a white, extremely dense, brittle, corrosion-resistant chemical element, one of the platinum metals: alloys of iridiumare used in electrodes, pen points, crucibles, etc.: symbol, Ir; at. no., 77
Word origin
ModL: so named (1804) by S. Tennant (1761-1815), Eng chemist < Gr iris (gen. iridos), iris, because its salts have varied colors; + -ium