Iridium

77
Ir
Gruppe
9
Periode
6
Blok
d
Protons
Electrons
Neutrons
77
77
115
General Properties
Atomnummer
77
Atommasse
192,217
Mass Number
192
Kategori
Overgangsmetaller
Farve
Silver
Radioactive
Nej
From the Latin word iris meaning rainbow
Krystalstruktur
Fladecentreret Kubisk
History
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.
Elektroner i hver skal
2, 8, 18, 32, 15, 2
Elektronkonfiguration
[Xe] 4f14 5d7 6s2
Ir
Iridium is the most corrosion-resistant metal known
Physical Properties
Tilstandsform
Fast stof
Massefylde
22,56 g/cm3
Smeltepunkt
2739,15 K | 2466 °C | 4470,8 °F
Kogepunkt
4701,15 K | 4428 °C | 8002,4 °F
Smeltevarme
26 kJ/mol
Fordampningsvarme
560 kJ/mol
Varmefylde
0,131 J/g·K
Abundance in Earth's crust
4×10-8%
Abundance in Universe
2×10-7%
Pieces
Billede akkrediteringer: Images-of-elements
Pieces of pure iridium
CAS Number
7439-88-5
PubChem CID Number
23924
Atomic Properties
Atomradius
136 pm
Kovalent radius
141 pm
Elektronegativitet
2,2 (Paulings skala)
Ionization Potential
8,967 eV
Atomic Volume
8,54 cm3/mol
Varmeledningsevne
1,47 W/cm·K
Oxidationstrin
-3, -1, 1, 2, 3, 4, 5, 6, 7, 8, 9
Applications
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
Isotoper
Stable Isotopes
191Ir, 193Ir
Unstable Isotopes
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