Iridium
77
Ir
Skupina
9
Perioda
6
Blok
d
Protony
Elektrony
Neutrony
77
77
115
Hlavní vlastnosti
Atomové číslo
77
Atomová hmotnost
192,217
Hmotnostní číslo
192
Kategorie
Přechodné kovy
Barva
Stříbrná
Radioaktivní
Ne
From the Latin word iris meaning rainbow
Krystalografická soustava
Krychlová plošně centrovaná
Historie
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.
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.
Elektronů v obalu
2, 8, 18, 32, 15, 2
Elektronová konfigurace
[Xe] 4f14 5d7 6s2
Iridium is the most corrosion-resistant metal known
Fyzické vlastnosti
Skupenství
Pevná
Hustota
22,56 g/cm3
Teplota tání
2739,15 K | 2466 °C | 4470,8 °F
Teplota varu
4701,15 K | 4428 °C | 8002,4 °F
Skupenské teplo tání
26 kJ/mol
Skupenské teplo varu
560 kJ/mol
Měrná tepelná kapacita
0,131 J/g·K
Hojnost v zemské kůře
4×10-8%
Hojnost ve vesmíru
2×10-7%
Číslo CAS
7439-88-5
PubChem CID číslo
23924
Atomové vlastnosti
Atomový poloměr
136 pm
Kovalentní poloměr
141 pm
Elektronegativita
2,2 (Paulingova stupnice)
Ionizační potenciál
8,967 eV
Molární objem
8,54 cm3/mol
Tepelná vodivost
1,47 W/cm·K
Oxidační čísla
-3, -1, 1, 2, 3, 4, 5, 6, 7, 8, 9
Aplikace
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 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
Izotopy
Stabilní izotopy
191Ir, 193IrNestabilní izotopy
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