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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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

  • Structure-property relationships based on Hammett constants in cyclometalated iridium(iii) complexes: their application to the design of a fluorine-free FIrPic-like emitter. Frey J, Curchod BF, Scopelliti R, Tavernelli I, Rothlisberger U, Nazeeruddin MK, Baranoff E. Dalton Trans. 2014
  • Asymmetric synthesis of 2,5-disubstituted 3-hydroxypyrrolidines based on stereodivergent intramolecular iridium-catalyzed allylic aminations. Natori Y, Kikuchi S, Kondo T, Saito Y, Yoshimura Y, Takahata H. Org Biomol Chem. 2014.
  • Mechanism of cellular accumulation of an iridium(iii) pentamethylcyclopentadienyl anticancer complex containing a C,N-chelating ligand. Novohradsky V, Liu Z, Vojtiskova M, Sadler PJ, Brabec V, Kasparkova J. Metallomics. 2014.
  • Ruthenium, Rhodium, Osmium, and Iridium Complexes of Osazones (Osazones = Bis-Arylhydrazones of Glyoxal): Radical versus Nonradical States. Patra SC, Weyhermüller T, Ghosh P. Inorg Chem. 2014.
  • A theoretical study on the injection, transport, absorption and phosphorescence properties of heteroleptic iridium(iii) complexes with different ancillary ligands. Shang X, Wan N, Han D, Zhang G. Photochem Photobiol Sci. 2014.
  • Iridium-catalyzed selective α-methylation of ketones with methanol. Ogawa S, Obora Y. Chem Commun (Camb). 2014.
  • Direct observation of reversible electronic energy transfer involving an iridium center. Denisov SA, Cudré Y, Verwilst P, Jonusauskas G, Marín-Suárez M, Fernández-Sánchez JF, Baranoff E, McClenaghan ND. Inorg Chem. 2014.
  • Correction to Iridium(III) Hydrido N-Heterocyclic Carbene-Phosphine Complexes as Catalysts in Magnetization Transfer Reactions. Fekete M, Bayfield OW, Duckett SB, Hart S, Mewis RE, Pridmore N, Rayner PJ, Whitwood A. Inorg Chem. 2014.
  • Distortion/Interaction Analysis Reveals the Origins of Selectivities in Iridium-Catalyzed C-H Borylation of Substituted Arenes and 5-Membered Heterocycles. Green AG, Liu P, Merlic CA, Houk KN. J Am Chem Soc. 2014.
  • Iridium-Catalyzed Intermolecular Amidation of sp3 C-H Bonds: Late-Stage Functionalization of an Unactivated Methyl Group. Kang T, Kim Y, Lee D, Wang Z, Chang S. J Am Chem Soc. 2014.
  • Controlling the Excited State and Photosensitizing Property of a 2-(2-Pyridyl)benzo[b]thiophene-Based Cationic Iridium Complex through Simple Chemical Modification. Takizawa SY, Shimada K, Sato Y, Murata S. Inorg Chem. 2014.
  • Oxygen Atom Transfer to a Half-Sandwich Iridium Complex: Clean Oxidation Yielding a Molecular Product. Turlington CR, White PS, Brookhart M, Templeton JL. J Am Chem Soc. 2014.
  • Electronic Conductivity of Films of Electroflocculated 2 nm Iridium Oxide Nanoparticles. Chow KF, Carducci TM, Murray RW. J Am Chem Soc. 2014.
  • Spontaneous assembly of iridium nanochain-like structures: surface enhanced Raman scattering activity using visible light. Chakrapani K, Sampath S. Chem Commun (Camb). 2014.
  • Iridium-catalyzed ortho-C-H borylation of aromatic aldimines derived from pentafluoroaniline with bis(pinacolate)diboron. Sasaki I, Amou T, Ito H, Ishiyama T. Org Biomol Chem. 2014.
  • Photoluminescence properties of a novel cyclometalated iridium(iii) complex with coumarin-boronate and its recognition of hydrogen peroxide. Li C, Wang S, Huang Y, Wen Q, Wang L, Kan Y. Dalton Trans. 2014.
  • Iridium-mediated regioselective B-h/c-h activation of carborane cage: a facile synthetic route to metallacycles with a carborane backbone. Yao ZJ, Yu WB, Lin YJ, Huang SL, Li ZH, Jin GX. J Am Chem Soc. 2014.
  • Sterically Directed Iridium-Catalyzed Hydrosilylation of Alkenes in the Presence of Alkynes. Muchnij JA, Kwaramba FB, Rahaim RJ. Org Lett. 2014.
  • Reversible Interconversion Between a Monomeric Iridium Hydroxo and a Dinuclear Iridium μ-Oxo Complex. Burford RJ, Piers WE, Ess DH, Parvez M. J Am Chem Soc. 2014.
  • Cyclometalated Iridium(III) Complexes for Phosphorescence Sensing of Biological Metal Ions. You Y, Cho S, Nam W. Inorg Chem. 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+