Osmium Elemental Symbol

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Osmium Osmium Osmio Ósmio Osmio Osmium

Osmium(Os) atomic and molecular weight, atomic number and elemental symbolOsmium is a Block D, Group 8, Period 6 element. The number of electrons in each of osmium's shells is 2, 8, 18, 32, 14, 2 and its electron configuration is [Xe] 4f14 5d6 6s2. The osmium atom has a radius of 133.8.pm and its Van der Waals radius is 216.pm. In its elemental form, CAS 7440-04-2, Osmium has a silvery blue cast apperance. Elemental Osmium Osmium has the highest melting point and the lowest vapor pressure of any of the platinum group of metals. Osmium Bohr ModelOsmium is the least abundant stable element in the earth's crust and is the densest stable element. It is found in the alloys osmiridium and iridiosmium and as an uncombined element. Osmium was first discovered by Smithson Tennant in 1803. The origin of the name Osmium comes from the Greek word osme meaning a smell or odor.

Osmium metal is almost entirely used to produce very hard alloys with other metals of the platinum group. Osmium tetroxide has recently been used to detect fingerprints and as an aid to stain fatty tissue for microscope slides. Osmium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Osmium (Os) Sputtering TargetElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. High Purity (99.999%) Osmium Oxide (OsO) PowderOsmium 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. Osmium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Osmium is extremely volatile and toxic in its oxide state. Safety data for Osmium 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
  • Safety Data
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  • Isotopes
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Osmium Properties

Symbol: Os Melting Point: 3306 K, 3033 °C, 5491 °F
Atomic Number: 76 Boiling Point: 5285 K, 5012 °C, 9054 °F
Atomic Weight: 190.23 Density: 22.59 g·cm−3
Element Category: transition metal Liquid Density @ Melting Point: 20 g·cm−3
Group, Period, Block: 8, 6, d Specific Heat: 0.13 (kJ/kg K)
    Heat of Vaporization 738.06 kJ mol-1
CHEMICAL STRUCTURE Heat of Fusion 29.3 kJ mol-1
Electrons: 76 Thermal Conductivity: 87.6 W·m−1·K−1
Protons: 76 Thermal Expansion: (25 °C) 5.1 µm·m−1·K−1
Neutrons: 114 Electrical Resistivity: (0 °C) 81.2 nΩ·m
Electron Configuration: [Xe] 4f145d66s2 Electronegativity: 2.2 (Pauling scale)
Atomic Radius: 135 pm Tensile Strength: N/A
Covalent Radius: 144±4 pm Molar Heat Capacity: 24.7 J·mol−1·K−1
Van der Waals radius: 216.pm Young's Modulus: N/A
Oxidation States: 8, 7, 6, 5, 4, 3, 2, 1, 0, -1, -2 (mildly acidic oxide) Shear Modulus: 222 GPa
Phase: Solid Bulk Modulus: 462 GPa
Crystal Structure: hexagonal close-packed Poisson Ratio: 0.25
Magnetic Ordering: paramagnetic Mohs Hardness: 7.0
1st Ionization Energy: 840 kJ·mol−1 Vickers Hardness: 3920 MPa
2nd Ionization Energy: 1600 kJ·mol−1 Brinell Hardness: N/A
3rd Ionization Energy: N/A Speed of Sound: (20 °C) 4940 m·s−1
CAS Number: 7440-04-2 Abundance in typical human body, by weight: N/A
ChemSpider ID: 23937 Abundance in typical human body, by atom: N/A
PubChem CID: 22379 Abundance in universe, by weight: 3 ppb
MDL Number: MFCD00011147 Abundance in universe, by atom: 0.02 ppb
EC Number: 231-114-0 Discovered By: Smithson Tennant
Beilstein Number: N/A Discovery Date: 1803
SMILES Identifier: [Os]  
InChI Identifier: InChI=1S/Os Other Names: Osmio

Health, Safety & Transportation Information for Osmium

Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H228-H315-H318-H335
Hazard Codes F, Xi
Risk Codes 11-37/38-41
Safety Precautions 16-26-36/37/39
RTECS Number RN1100000
Transport Information UN 3089 4.1/PG 2
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
Exclamation Mark-Acute Toxicity Corrosion-Corrosive to metals Flame-Flammables  

Osmium Products

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

Recent Research & Development for Osmium

  • Deming Han, Jian Liu, Runzhong Miao, Lihui Zhao, Gang Zhang, Theoretical design study on the electronic structure and photophysical properties of a series of osmium(II) complexes with different ancillary ligands, Polyhedron, Volume 85, 8 January 2015
  • Xiaoting Chen, Conghui Si, Yulai Gao, Jan Frenzel, Junzhe Sun, Gunther Eggeler, Zhonghua Zhang, Multi-component nanoporous platinum–ruthenium–copper–osmium–iridium alloy with enhanced electrocatalytic activity towards methanol oxidation and oxygen reduction, Journal of Power Sources, Volume 273, 1 January 2015
  • Deisy Peña, Yomaira Otero, Alejandro Arce, Lenin Díaz, Ysaura De Sanctis, Edgar Ocando–Mavarez, Juan M. García, Rubén Machado, Teresa González, Synthesis and characterization of trinuclear osmium clusters containing diallylphosphines as hemilabile ligands: Experimental and theoretical studies of their reactivity with nucleophilic molecules, Journal of Organometallic Chemistry, Volumes 772–773, 1 December 2014
  • Gajendra Gupta, Narayana Nagesh, Benjamin S. Murray, Paul J. Dyson, Bruno Therrien, Antiproliferative activities of trithiolato-bridged dinuclear arene osmium complexes, Inorganica Chimica Acta, Volume 423, Part A, 1 November 2014
  • Zhenggang Xu, Michael B. Hall, Computational study of the cycloaddition reactivity of the osmium silylyne, Inorganica Chimica Acta, Volume 422, 1 October 2014
  • Wai-Man Cheung, Ho-Yuen Ng, Herman H.-Y. Sung, Ian D. Williams, Wa-Hung Leung, Dinuclear osmium(IV) oxo complexes with a dithioimidodiphosphinate ligand, Inorganica Chimica Acta, Volume 422, 1 October 2014
  • Mikhail M. Vinogradov, Lidia S. Shul'pina, Yuriy N. Kozlov, Alexander R. Kudinov, Nikolay S. Ikonnikov, Georgiy B. Shul'pin, Oxidation of hydrocarbons and alcohols with peroxides catalyzed by new π-cymene osmium complexes, Journal of Organometallic Chemistry, Available online 9 August 2014
  • Yifei Liu, Peter I. Djurovich, Ralf Haiges, Mark E. Thompson, Synthesis and photophysical characterization of a bis-pincer osmium complex, Polyhedron, Available online 11 July 2014
  • Horst Kunkely, Arnd Vogler, Photochemistry of osmocene. Reductive elimination and generation of elemental osmium, Inorganic Chemistry Communications, Volume 44, June 2014
  • Diana M. Fernandes, Johannes G. Vos, Cristina Freire, Europium phosphomolybdate and osmium metallopolymer multi-functional LbL films: Redox and electrocatalytic properties, Journal of Colloid and Interface Science, Volume 420, 15 April 2014

Osmium Isotopes

Osmium (Os) has seven naturally occurring isotopes. Six of them are stable: 184Os, 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. One of them, 186Os, has an extremely long half-life (2×1015 years)

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
184Os 183.9524891 Observationally Stable 0+
186Os 185.9538382 2.0(11)×1015 a 0+
187Os 186.9557505 Observationally Stable 1/2-
188Os 187.9558382 Observationally Stable 0+
189Os 188.9581475 Observationally Stable 3/2-
190Os 189.9584470 Observationally Stable 0+
192Os 191.9614807 Observationally Stable 0+