Iridium

77
Ir
Gruppe
9
Periode
6
Block
d
Protonen
Elektronen
Neutronen
77
77
115
Generelle Eigenschaften
Ordnungszahl
77
Atommasse
192,217
Massenzahl
192
Kategorie
Übergangsmetalle
Farbe
Silber
Radioaktiv
Nein
Aus dem Lateinischen iris (Regenbogen)
Kristallstruktur
Kubisch flächenzentriert
Geschichte
Iridium was discovered in 1803 by English chemist Smithson Tennant in London.

Chemists who studied platinum dissolved it in aqua regia to create soluble salts and observed a small amount of a dark, insoluble residue.

Smithson Tennant analyzed the insoluble residue and concluded that it must contain a new metal.
Elektronen pro Schale
2, 8, 18, 32, 15, 2
Elektronenkonfiguration
[Xe] 4f14 5d7 6s2
Ir
Iridium is the most corrosion-resistant metal known
Physikalische Eigenschaften
Aggregatzustand
Fest
Dichte
22,56 g/cm3
Schmelzpunkt
2739,15 K | 2466 °C | 4470,8 °F
Siedepunkt
4701,15 K | 4428 °C | 8002,4 °F
Schmelzwärme
26 kJ/mol
Verdampfungswärme
560 kJ/mol
Spezifische Wärmekapazität
0,131 J/g·K
Häufigkeit in der Erdkruste
4×10-8%
Häufigkeit im Universum
2×10-7%
Pieces
Danksagungen für Bilder: Images-of-elements
Pieces of pure iridium
CAS-Nummer
7439-88-5
PubChem CID Number
23924
Atomeigenschaften
Atomradius
136 pm
Kovalenter Radius
141 pm
Elektronegativität
2,2 (Pauling-Skala)
Ionisierungsenergie
8,967 eV
Molares Volumen
8,54 cm3/mol
Wärmeleitfähigkeit
1,47 W/cm·K
Oxidationszustände
-3, -1, 1, 2, 3, 4, 5, 6, 7, 8, 9
Anwendung
Iridium is used in making crucibles and other equipment that is used at high temperatures.

Iridium is also used as a hardening agent in platinum alloys.

Its resistance to arc erosion makes iridium alloys ideal for electrical contacts for spark plugs.

Radioactive isotopes of iridium are used in radiation therapy for the treatment of cancer.
Iridium is considered to be of low toxicity
Isotope
Stabile Isotope
191Ir, 193Ir
Instabile Isotope
164Ir, 165Ir, 166Ir, 167Ir, 168Ir, 169Ir, 170Ir, 171Ir, 172Ir, 173Ir, 174Ir, 175Ir, 176Ir, 177Ir, 178Ir, 179Ir, 180Ir, 181Ir, 182Ir, 183Ir, 184Ir, 185Ir, 186Ir, 187Ir, 188Ir, 189Ir, 190Ir, 192Ir, 194Ir, 195Ir, 196Ir, 197Ir, 198Ir, 199Ir