Iridium

Kemiallinen merkki: Ir
Järjestysluku: 77
Kategoria: siirtymämetallit
Ryhmä: 9
Jakso: 6
Lohko: d
Moolimassa: 192,217 g/mol
Elektronia kuorilla: 2, 8, 18, 32, 15, 2
CAS-numero: 7439-88-5
Olomuoto: kiinteä
Tiheys: 22,56 kg/l (lähellä huoneenlämpöä)
Sulamispiste: 2739 K (2466 °C, 4471 °F)
Kiehumispiste: 4701 K (4428 °C, 8002 °F)
Kiderakenne: cubic face centered
Hapetusluvut: -3,-1, 0, 1, 2, 3, 4, 5, 6
Elektronegatiivisuus: 2,20 (Pauling-asteikko)
Nimen alkuperä: Iris
Nimen tarkoitus: the Greek winged goddess of the rainbow and the messenger of the Olympian gods, because many of the salts he obtained were strongly colored
Faktoja:
- a very hard, brittle, silvery-white transition metal of the platinum family
- is the second densest element and is the most corrosion- resistant metal, even at temperatures as high as 2000 C
- is one of the rarest elements in the Earth's c
- annual production and consumption is only three tonnes
- iridium compounds also find applications as catalysts for the production of acetic acid
- is used in spark plugs, crucibles for recrystallization of semiconductors at high temperatures, electrodes for the production of chlorine in the chloralkali process, and radioisotope thermoelectric generators used in unmanned spacecraft