Iridium

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Iridium,  77Ir
Twa square pieces o gray foil
General properties
Name, seembol iridium, Ir
Pronunciation /ɨˈrɪdiəm/
i-RID-ee-əm
Appearance sillery white
Iridium in the periodic cairt
Hydrogen (diatomic nonmetal)
Helium (noble gas)
Lithium (alkali metal)
Beryllium (alkaline yird metal)
Boron (metalloid)
Carbon (polyatomic nonmetal)
Nitrogen (diatomic nonmetal)
Oxygen (diatomic nonmetal)
Fluorine (diatomic nonmetal)
Neon (noble gas)
Sodium (alkali metal)
Magnesium (alkaline yird metal)
Aluminium (post-transeetion metal)
Silicon (metalloid)
Phosphorus (polyatomic nonmetal)
Sulfur (polyatomic nonmetal)
Chlorine (diatomic nonmetal)
Argon (noble gas)
Potassium (alkali metal)
Calcium (alkaline yird metal)
Scandium (transeetion metal)
Titanium (transeetion metal)
Vanadium (transeetion metal)
Chromium (transeetion metal)
Manganese (transeetion metal)
Iron (transeetion metal)
Cobalt (transeetion metal)
Nickel (transeetion metal)
Copper (transeetion metal)
Zinc (transeetion metal)
Gallium (post-transeetion metal)
Germanium (metalloid)
Arsenic (metalloid)
Selenium (polyatomic nonmetal)
Bromine (diatomic nonmetal)
Krypton (noble gas)
Rubidium (alkali metal)
Strontium (alkaline yird metal)
Yttrium (transeetion metal)
Zirconium (transeetion metal)
Niobium (transeetion metal)
Molybdenum (transeetion metal)
Technetium (transeetion metal)
Ruthenium (transeetion metal)
Rhodium (transeetion metal)
Palladium (transeetion metal)
Silver (transeetion metal)
Cadmium (transeetion metal)
Indium (post-transeetion metal)
Tin (post-transeetion metal)
Antimony (metalloid)
Tellurium (metalloid)
Iodine (diatomic nonmetal)
Xenon (noble gas)
Caesium (alkali metal)
Barium (alkaline yird metal)
Lanthanum (lanthanide)
Cerium (lanthanide)
Praseodymium (lanthanide)
Neodymium (lanthanide)
Promethium (lanthanide)
Samarium (lanthanide)
Europium (lanthanide)
Gadolinium (lanthanide)
Terbium (lanthanide)
Dysprosium (lanthanide)
Holmium (lanthanide)
Erbium (lanthanide)
Thulium (lanthanide)
Ytterbium (lanthanide)
Lutetium (lanthanide)
Hafnium (transeetion metal)
Tantalum (transeetion metal)
Tungsten (transeetion metal)
Rhenium (transeetion metal)
Osmium (transeetion metal)
Iridium (transeetion metal)
Platinum (transeetion metal)
Gold (transeetion metal)
Mercury (transeetion metal)
Thallium (post-transeetion metal)
Lead (post-transeetion metal)
Bismuth (post-transeetion metal)
Polonium (post-transeetion metal)
Astatine (metalloid)
Radon (noble gas)
Francium (alkali metal)
Radium (alkaline yird metal)
Actinium (actinide)
Thorium (actinide)
Protactinium (actinide)
Uranium (actinide)
Neptunium (actinide)
Plutonium (actinide)
Americium (actinide)
Curium (actinide)
Berkelium (actinide)
Californium (actinide)
Einsteinium (actinide)
Fermium (actinide)
Mendelevium (actinide)
Nobelium (actinide)
Lawrencium (actinide)
Rutherfordium (transeetion metal)
Dubnium (transeetion metal)
Seaborgium (transeetion metal)
Bohrium (transeetion metal)
Hassium (transeetion metal)
Meitnerium (unkent chemical properties)
Darmstadtium (unkent chemical properties)
Roentgenium (unkent chemical properties)
Copernicium (transeetion metal)
Ununtrium (unkent chemical properties)
Flerovium (post-transeetion metal)
Ununpentium (unkent chemical properties)
Livermorium (unkent chemical properties)
Ununseptium (unkent chemical properties)
Ununoctium (unkent chemical properties)
Rh

Ir

Mt
osmiumiridiumplatinum
Atomic nummer 77
Staundart atomic wicht (Ar) 192.217
Element category   transeetion metal
Group, block group 9, d-block
Period period 6
Electron configuration [Xe] 4f14 5d7 6s2
per shell
2, 8, 18, 32, 15, 2
Pheesical properties
Phase solid
Meltin pynt 2739 K ​(2466 °C, ​4471 °F)
Boilin pynt 4701 K ​(4428 °C, ​8002 °F)
Density near r.t. 22.56 g/cm3
when liquid, at m.p. 19 g/cm3
Heat o fusion 41.12 kJ/mol
Heat o 563 kJ/mol
Molar heat capacity 25.10 J/(mol·K)
 pressure
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, 8
Electronegativity Pauling scale: 2.20
Atomic radius empirical: 136 pm
Covalent radius 141±6 pm
Miscellanea
Crystal structur face-centered cubic (fcc)
Face-centered cubic crystal structure for iridium
Speed o soond thin rod 4825 m/s (at 20 °C)
Thermal expansion 6.4 µm/(m·K)
Thermal conductivity 147 W/(m·K)
Electrical resistivity 47.1 n Ω·m (at 20 °C)
Magnetic orderin paramagnetic[1]
Young's modulus 528 GPa
Shear modulus 210 GPa
Bulk modulus 320 GPa
Poisson ratio 0.26
Mohs haurdness 6.5
Vickers haurdness 1760 MPa
Brinell haurdness 1670 MPa
CAS Registry Nummer 7439-88-5
History
Discovery Smithson Tennant (1803)
First isolation Smithson Tennant (1803)
Maist stable isotopes
Main article: Isotopes o iridium
iso NA hauf-life DM DE (MeV) DP
188Ir syn 1.73 d ε 1.64 188Os
189Ir syn 13.2 d ε 0.532 189Os
190Ir syn 11.8 d ε 2.000 190Os
191Ir 37.3% - (α) 2.0839 187Re
192Ir syn 73.827 d β 1.460 192Pt
ε 1.046 192Os
192m2Ir syn 241 y IT 0.161 192Ir
193Ir 62.7% - (α) 1.0173 189Re
193mIr syn 10.5 d IT 0.080 193Ir
194Ir syn 19.3 h β 2.247 194Pt
194m2Ir syn 171 d IT - 194Ir
Decay modes in parentheses are predictit, but hae nae yet been observed
· references

Iridium is the chemical element wi seembol Ir an atomic nummer 77. A very hard, brittle, sillery-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. Altho anly certain molten sauts an halogens are corrosive tae solid iridium, finely dividit iridium dust is much mair reactive an can be flammable.

References[eedit | eedit soorce]

  1. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.