Osmium

Osmium (Os)

Hard blue-white metallic transition element. Found with platinum and used in some alloys with platinum and iridium.
Atomic Number76
Atomic Weight190.23
Mass Number192
Group8
Period6
Blockd
Protons76 p+
Neutrons116 n0
Electrons76 e-
Osmium crystals.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
130 pm
Atomic Volume
Covalent Radius
129 pm
Metallic Radius
126 pm
Ionic Radius
63 pm
Crystal Radius
77 pm
Van der Waals radius
216 pm
Density
22.5872 g/cm³
Boiling Point
5,300 K
Melting Point
3,327 K
Electrons per shell2, 8, 18, 32, 14, 2
Electronegativity
2.2
Electrophilicity
1.5497236992589 eV/particle
Proton Affinity
Electron Affinity
Ionization Potential
8.43823 eV/particle
Heat of Vaporization
738 kJ/mol
Heat of Fusion
31.7 kJ/mol
Heat of Formation
787 kJ/mol
Molar Heat Capacity
Specific Heat Capacity
Thermal Conductivity
Gas Basicity
Dipole Polarizability
57 a₀
C6 Dispersion Coefficient
Oxidation States-2, 1, 2, 3, 4, 5, 6, 7, 8
Color
Slate Gray
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
2.74 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Xe] 4f14 5d6 6s2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryTransition metals, Transition metals
CAS GroupVIIIA
IUPAC GroupVIII
Glawe Number60
Mendeleev Number61
Pettifor Number62
Geochemical Classnoble metal
Goldschmidt Classsiderophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
0.0015 mg/kg
Abundance in Oceans
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe3×10-7%

Isotopes of Osmium

Stable Isotopes
184Os 186Os 187Os 188Os 189Os 190Os 192Os
Unstable Isotopes
162Os 163Os 164Os 165Os 166Os 167Os 168Os 169Os 170Os 171Os 172Os 173Os 174Os 175Os 176Os 177Os 178Os 179Os 180Os 181Os 182Os 183Os 185Os 191Os 193Os 194Os 195Os 196Os

History

Osmium was discovered in 1803 by English chemist Smithson Tennant in London. Chemists who studied platinum dissolved it in aqua regia to create soluble salts and observed a small amount of a dark, insoluble residue. Smithson Tennant analyzed the insoluble residue and concluded that it must contain a new metal. From the Greek word osme, meaning smell

DiscoverersSmithson Tenant
Discovery LocationEngland
Discovery Year1804
Name OriginGreek: osmê (odor).
Even low concentrations in air can cause lung congestion, skin damage, or eye damage
Osmium is the least abundant stable element in the Earth's crust

Uses

Osmium is used alloyed with other metals in the platinum group to produce very hard alloys. Osmium alloys are used in the tips of fountain pens, instrument pivots, and electrical contacts Osmium tetroxide has been used in fingerprint detection and in staining fatty tissue for optical and electron microscopy. Used to tip gold pen points, instrument pivots, to make electric light filaments. Used for high temp. alloys and pressure bearings. Very hard and resists corrosion better than any other.

Sources

Obtained from the same ores as platinum.