Iridium Elemental Symbol

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Iridium Iridium Iridio Irídio Irídio Iridium

Iridium(Ir) atomic and molecular weight, atomic number and elemental symbolIridium is a Block D, Group 9, Period 6 element. The number of electrons in each of iridium's shells is 2, 8, 18, 32, 15, 2 and its electron configuration is [Xe] 4f14 5d7 6s2. Elemental IridiumThe iridium atom has a radius of and its Van der Waals radius is Iridium Bohr ModelIn its elemental form, CAS 7439-88-5, Iridium has a silvery white appearance. Iridium is a member of the platinum group of metals. It is the most corrosion resistant metal known and is the second-densest element (after osmium). It will not react with any acid and can only be attacked by certain molten salts, such as molten sodium chloride. Iridium is found as an uncombined element and in iridium-osmium alloys. Iridium was first discovered by Smithson Tennant in 1803. Iridium's name is derived from the Greek goddess Iris, personification of the rainbow, on account of the striking and diverse colors of its salts.

Iridium is alloyed with platinum to produce highly corrosion resistant electrical contacts for spark plugs. High Purity (99.999%) Iridium Oxide (IrO2) PowderIridium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Iridium (Ir)Sputtering TargetElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Iridium nanoparticles and nanopowders provide ultra-high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Iridium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Iridium is only slightly toxic in its elemental form; however, safety data for Iridium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab below.

  • Properties
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  • Isotopes
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Iridium Properties

Symbol: Ir Melting Point: 2739 K, 2466 °C, 4471 °F
Atomic Number: 77 Boiling Point: 4701 K, 4428 °C, 8002 °F
Atomic Weight: 192.217 Density: 22.56 g·cm−3
Element Category: transition metal Liquid Density @ Melting Point: 19 g·cm−3
Group, Period, Block: 9, 6, d Specific Heat: 0.13 (kJ/kg K)
    Heat of Vaporization 612.1 kJ mol-1
CHEMICAL STRUCTURE Heat of Fusion 26.4 kJ mol-1
Electrons: 77 Thermal Conductivity: 147 W·m−1·K−1
Protons: 77 Thermal Expansion: 6.4 µm/(m·K)
Neutrons: 115 Electrical Resistivity: (20 °C) 47.1 nΩ·m
Electron Configuration: [Xe] 4f145d76s2 Electronegativity: 2.20 (Pauling scale)
Atomic Radius: Tensile Strength: N/A
Covalent Radius: 141± Molar Heat Capacity: 25.10 J·mol−1·K−1
Van der Waals radius: Young's Modulus: 528 GPa
Oxidation States: −3,−1, 0, 1, 2, 3, 4, 5, 6 Shear Modulus: 210 GPa
Phase: Solid Bulk Modulus: 320 GPa
Crystal Structure: face-centered cubic Poisson Ratio: 0.26
Magnetic Ordering: paramagnetic Mohs Hardness: 6.5
1st Ionization Energy: 880 kJ·mol−1 Vickers Hardness: 1760 MPa
2nd Ionization Energy: 1600 kJ·mol−1 Brinell Hardness: 1670 MPa
3rd Ionization Energy: N/A Speed of Sound: (20 °C) 4825 m·s−1
CAS Number: 7439-88-5 Abundance in typical human body, by weight: N/A
ChemSpider ID: 22367 Abundance in typical human body, by atom: N/A
PubChem CID: 23924 Abundance in universe, by weight: 2 ppb
MDL Number: MFCD00011062 Abundance in universe, by atom: 0.01 ppb
EC Number: 231-095-9 Discovered By: Smithson Tennant
Beilstein Number: N/A Discovery Date: 1803
SMILES Identifier: [Ir]  
InChI Identifier: InChI=1S/Ir Other Names: Iridio

Iridium Products

Metal Forms  •  Compounds  •  Alloys  •  Oxide Forms  •  Organometallic Compounds
Sputtering Targets  •  Nanomaterials  •  Semiconductor Materials •  Isotopes

Organometallic Compounds

(1,5-Cyclooctadiene)(methoxy)iridium(I) Dimer



(2,4-Pentanedionato-O2,O4)bis[2-(1H -pyrazol-1-yl-N2)phenyl

Bis(1,5-cyclooctadiene)diiridium(I) dichloride
Bis(1,5-cyclooctadiene)iridium(I) Tetrafluoroborate
Bis[1,2-bis(diphenylphosphino) ethane]carbonyl chloroiridium(I)
Bis(cyclooctadiene)iridium(I) tetrakis(3,5-bis(trifluoromethyl)phenyl)borate
Carbonylchlorobis(triphenylphosphine) iridium(I)
Carbonylhydridotris (triphenylphosphine)iridium(I)
Chloro(1,5-cyclooctadiene)iridium(I) Dimer
Chlorodihydrido[bis(2-diisopropylphosphino)ethylamine]iridium(III), Mixture of Isomers
Diiodo(pentamethylcyclopentadienyl)iridium(III) dimer
Iridium Acetylacetonate
Iridium(IV) Chloride Hydrate
Iridium 2 - Ethylhexanoate
Iridium(I) Hexafluorophosphate
Iridium(IV) Oxide Hydrate
Iridium(III) 2,4-pentanedionate
Iridium Trifluoromethanesulfonate
Pentaamminechloroiridium(III) Chloride
Pentamethylcyclopentadienyliridium(III) Chloride, dimer

Crystal/ Semiconductor Materials

Iridium Phosphide
Iridium Selenide
Iridium Silicide
Iridium Sulfide
Iridium Telluride


Iridium Manganese
Platinum Iridium Alloy
Platinum/Iridium Foil
Platinum/Iridium Tube
Platinum/Iridium Wire

Recent Research & Development for Iridium

  • Tongtong Li, Malin Cui, Guoxia Ran, Qijun Song, Ionic iridium complexes with conjugated phenyl substituent: Synthesis and DFT calculation on the electrochemical and electrochemiluminescent properties, Dyes and Pigments, Volume 112, January 2015
  • Hong-Tao Cao, Guo-Gang Shan, Yong-Ming Yin, Hai-Zhu Sun, Yong Wu, Wen-Fa Xie, Zhong-Min Su, Modification of iridium(III) complexes for fabrication of high-performance non-doped organic light-emitting diode, Dyes and Pigments, Volume 112, January 2015
  • Yige Qi, Xu Wang, Ming Li, Zhiyun Lu, Junsheng Yu, Highly efficient and concentration-insensitive organic light-emitting devices based on self-quenching-resistant orange–red iridium complex, Journal of Luminescence, Volume 155, November 2014
  • Chun Liu, Xiaofeng Rao, Xin Lv, Jieshan Qiu, Zilin Jin, Substituent effects on the photophysical and electrochemical properties of iridium(III) complexes containing an arylcarbazolyl moiety, Dyes and Pigments, Volume 109, October 2014
  • Shunliang Zhou, Qi Wang, Ming Li, Zhiyun Lu, Junsheng Yu, Highly efficient and heavily-doped organic light-emitting devices based on an orange phosphorescent iridium complex, Journal of Luminescence, Volume 154, October 2014
  • Arnab Kumar Maity, Manish Bhattacharjee, Sujit Roy, SnCl2 insertion into Ir–Cl and Rh–Cl bonds: Synthesis, characterization and catalytic activity of three-legged piano-stool trichlorostannyl iridium and rhodium complexes, Journal of Organometallic Chemistry, Volume 768, 1 October 2014
  • Woosum Cho, Yulhee Kim, Chikyu Lee, Juhyeon Park, Yeong-Soon Gal, Jae Wook Lee, Sung-Ho Jin, Single emissive layer white phosphorescent organic light-emitting diodes based on solution-processed iridium complexes, Dyes and Pigments, Volume 108, September 2014
  • Mahesh Kalidasan, S.H. Forbes, Yurij Mozharivskyj, Mohan Rao Kollipara, Half-sandwich ?6-arene ruthenium and Cp* rhodium/iridium compounds comprising with thioether ligands: Synthesis, spectral and molecular studies, Inorganica Chimica Acta, Volume 421, 1 September 2014
  • Yi-Ming Jin, Cheng-Cheng Wang, Li-Sha Xue, Tian-Yi Li, Song Zhang, Xuan Liu, Xiao Liang, You-Xuan Zheng, Jing-Lin Zuo, Efficient organic light-emitting diodes with low efficiency roll-off using iridium emitter with 2-(5-phenyl-1,3,4-oxadiazol-2-yl)phenol as ancillary ligand, Journal of Organometallic Chemistry, Volume 765, 15 August 2014
  • Marion Graf, Yvonne Gothe, Nils Metzler-Nolte, Rafal Czerwieniec, Karlheinz Sünkel, Photophysical and biological characterization of new cationic cyclometalated M(III) complexes of rhodium and iridium, Journal of Organometallic Chemistry, Volume 765, 15 August 2014
  • Chen-Hao Wang, Hsin-Cheng Hsu, Kai-Ching Wang, Iridium-decorated Palladium–Platinum core–shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell, Journal of Colloid and Interface Science, Volume 427, 1 August 2014
  • Taiju Tsuboi, Duo-Fong Huang, Tahsin J. Chow, Wei Huang, Four emission bands from a mixed-ligand iridium complex IrQ(ppy)2 at room temperature, Optical Materials, Volume 36, Issue 10, August 2014
  • Li Wang, Na Wang, Yanxin Zhang, Hongqing He, Jinglai Zhang, Color tuning from red to green of bis-cyclometalated iridium(III) emitters based on benzoimidazole ligands in OLEDs: A DFT and TD-DFT investigation, Synthetic Metals, Volume 194, August 2014
  • Lu Li, Xiuhui Zhang, Qian-shu Li, R. Bruce King, Butterfly versus Tetrahedral Cluster Structures for the Unsaturated Tetracobalt Carbonyls Co4(CO)n (n = 10, 9): Major Differences between Cobalt and Iridium, Polyhedron, Available online 14 July 2014
  • Keith Man-Chung Wong, Chunyan Wang, Ho-Chuen Lam, Nianyong Zhu, Bichromophoric rhodamine-rhenium(I) and -Iridium(III) sensory system: Synthesis, characterizations, photophysical and selective metal ions binding studies, Polyhedron, Available online 14 July 2014
  • Min Chen, Yongquan Wu, Yi Liu, Huiran Yang, Qiang Zhao, Fuyou Li, A phosphorescent iridium(III) solvent complex for multiplex assays of cell death, Biomaterials, Available online 9 July 2014
  • David M. Morris, Michael McGeagh, David De Peña, Joseph S. Merola, Extending the Range of Pentasubstituted Cylopentadienyl Compounds: the Synthesis of a Series of Tetramethyl(alkyl or aryl)cyclopentadienes (Cp*R), Their Iridium Complexes and Their Catalytic Activity for Assymetric Transfer Hydrogenation, Polyhedron, Available online 8 July 2014
  • Bihai Tong, Peng Ma, Qunbo Mei, Zhongsheng Hua, Synthesis, photophysical properties and electrochemiluminescence performances of a series of cationic iridium(III) complexes, Inorganica Chimica Acta, Available online 3 July 2014
  • Xiao Li, Tie-Nan Zang, Hai-Jun Chi, Yan Dong, Guo-Yong Xiao, Dong-Yu Zhang, Multifunctional phosphorescent iridium (III) complexes based on 2-phenylbenzothiazole derivative for highly efficient organic light-emitting diodes, Dyes and Pigments, Volume 106, July 2014
  • Jayaraman Jayabharathi, Karunamoorthy Jayamoorthy, Venugopal Thanikachalam, Synthesis, photophysical and electroluminescent properties of green organic light emitting devices based on novel iridium complexes containing benzimidazole ligands, Journal of Organometallic Chemistry, Volume 761, 1 July 2014

Iridium Isotopes

There are two natural isotopes of iridium (Ir): 191Ir and 193Ir.

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
191Ir 190.9605940 Observationally Stable 3/2+
193Ir 192.9629264 Observationally Stable 3/2+