Iridium

Iridium, ₇₇Ir
Iridium
Pronunciation	/ɪˈrɪdiəm/ (ih-RID-ee-əm)
Appearance	sillery white
Standard atomic weight Ar, std(Ir)	192.217(2)
Iridium in the periodic cairt
	osmium ← iridium → platinum
Atomic nummer (Z)	77
Group	group 9
Period	period 6
Block	d-block
Element category	Transeetion metal
Electron confeeguration	[Xe] 4f14 5d7 6s2
Electrons per shell	2, 8, 18, 32, 15, 2
Pheesical properties
Phase at STP	solid
Meltin pynt	2719 K (2446 °C, 4435 °F)
Bylin pynt	4403 K (4130 °C, 7466 °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 vapourisation	564 kJ/mol
Molar heat capacity	25.10 J/(mol·K)
Atomic properties
Oxidation states	−3, −1, 0, +1, +2, +3, +4, +5, +6, +7, +8, +9
Electronegativity	Pauling scale: 2.20
Ionisation energies	1st: 880 kJ/mol ; 2nd: 1600 kJ/mol ; ;
Atomic radius	empirical: 136 pm
Covalent radius	141±6 pm
	Colour lines in a spectral rangeSpectral lines o iridium
Ither properties
Naitural occurrence	primordial
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 rod	4825 m/s (at 20 °C)
Thermal expansion	6.4 µm/(m·K)
Thermal conductivity	147 W/(m·K)
Electrical resistivity	47.1 nΩ·m (at 20 °C)
Magnetic orderin	paramagnetic
Magnetic susceptibility	+25.6·10−6 cm3/mol (298 K)
Young's modulus	528 GPa
Shear modulus	210 GPa
Bulk modulus	320 GPa
Poisson ratio	0.26
Mohs haurdness	6.5
Vickers haurdness	1760–2200 MPa
Brinell haurdness	1670 MPa
CAS Nummer	7439-88-5
History
Diskivery an first isolation	Smithson Tennant (1803)
Main isotopes o iridium
ε	192Os
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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.

References

↑ 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.
↑ ^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
↑ 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.
↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[CIAAW2013-1] 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.

[IrIX-2] 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.

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