Symbol Ir. A silvery metallic transition element (see also platinum metals); a.n. 77; r.a.m. 192.20; r.d. 22.42; m.p. 2410°C; b.p. 4130°C. It occurs with platinum and is mainly used in alloys with platinum and osmium. The element forms a range of iridium(III) and iridium(IV) complexes. It was discovered in 1804 by Smithson Tennant (1761–1815).
http://www.webelements.com/webelements/elements/text/Ir/key.htm Information from the WebElements site