Iridium is the chemical element wi seembol Ir an atomic nummer 77. A vera haurd, brickle, siller-white transeetion metal o the platinum faimily, iridium is the seicont-densest element (efter osmium) an is the maist corrosion-resistant metal, even at temperaturs as heich as 2000 °C. Tho anerly certaint molten sauts an halogens is corrosive tae solit iridium, finely dividit iridium dust is a fair bit mair reactive an can be flammable.

Iridium, 77Ir
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Iridium
Pronunciation/ɪˈrɪdiəm/ (ih-RID-ee-əm)
Appearancesillery white
Standard atomic weight Ar, std(Ir)192.217(2)[1]
Iridium in the periodic cairt
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Rh

Ir

Mt
osmiumiridiumplatinum
Atomic nummer (Z)77
Groupgroup 9
Periodperiod 6
Blockd-block
Element category  Transeetion metal
Electron confeeguration[Xe] 4f14 5d7 6s2
Electrons per shell2, 8, 18, 32, 15, 2
Pheesical properties
Phase at STPsolid
Meltin pynt2719 K ​(2446 °C, ​4435 °F)
Bylin pynt4403 K ​(4130 °C, ​7466 °F)
Density (near r.t.)22.56 g/cm3
when liquid (at m.p.)19 g/cm3
Heat o fusion41.12 kJ/mol
Heat o vapourisation564 kJ/mol
Molar heat capacity25.10 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2713 2957 3252 3614 4069 4659
Atomic properties
Oxidation states−3, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8, +9[2]
ElectronegativityPauling scale: 2.20
Ionisation energies
  • 1st: 880 kJ/mol
  • 2nd: 1600 kJ/mol
Atomic radiusempirical: 136 pm
Covalent radius141±6 pm
Colour lines in a spectral range
Colour lines in a spectral range
Spectral lines o iridium
Ither properties
Naitural occurrenceprimordial
Creestal structur ​face-centred cubic
[[File:face-centred cubic|frameless|alt=Face-centred cubic creestal structur for iridium|upright=0.23|Face-centred cubic creestal structur for iridium]]
Speed o soond thin rod4825 m/s (at 20 °C)
Thermal expansion6.4 µm/(m·K)
Thermal conductivity147 W/(m·K)
Electrical resistivity47.1 nΩ·m (at 20 °C)
Magnetic orderinparamagnetic[3]
Magnetic susceptibility+25.6·10−6 cm3/mol (298 K)[4]
Young's modulus528 GPa
Shear modulus210 GPa
Bulk modulus320 GPa
Poisson ratio0.26
Mohs haurdness6.5
Vickers haurdness1760–2200 MPa
Brinell haurdness1670 MPa
CAS Nummer7439-88-5
History
Diskivery an first isolationSmithson Tennant (1803)
Main isotopes o iridium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
188Ir syn 1.73 d ε 188Os
189Ir syn 13.2 d ε 189Os
190Ir syn 11.8 d ε 190Os
191Ir 37.3% stable
192Ir syn 73.827 d β 192Pt
ε 192Os
192m2Ir syn 241 y IT 192Ir
193Ir 62.7% stable
193mIr syn 10.5 d IT 193Ir
194Ir syn 19.3 h β 194Pt
194m2Ir syn 171 d IT 194Ir
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References

eedit
  1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  2. a b Wang, Guanjun; Zhou, Mingfei; Goettel, James T.; Schrobilgen, Gary G.; Su, Jing; Li, Jun; Schlöder, Tobias; Riedel, Sebastian (2014). "Identification of an iridium-containing compound with a formal oxidation state of IX". Nature. 514 (7523): 475–477. Bibcode:2014Natur.514..475W. doi:10.1038/nature13795. PMID 25341786. Cite error: Invalid <ref> tag; name "IrIX" defined multiple times wi different content
  3. Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  4. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.