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 of Os (Osmium) Enhanced Bohr Model of Os (Osmium) Bohr Model: Os (Osmium) Orbital Diagram of Os (Osmium)

Properties

Atomic Radius
130 pm
Molar 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
Energy
Proton Affinity
Electron Affinity
Ionization Energy
8.43823 eV/particle
Heat of Vaporization
738 kJ/mol
Heat of Fusion
31.7 kJ/mol
Heat of Formation
787 kJ/mol
Electrons
Electron Shells2, 8, 18, 32, 14, 2
Valence Electrons6
Electron Configuration[Xe] 4f14 5d6 6s2
Oxidation States-4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8
Electronegativity
2.2
Electrophilicity
1.5497236992588812 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
5,281.15 K
Melting Point
3,306.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Slate Gray
Appearancesilvery, blue cast
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
0.0000051 1/K
Molar Heat Capacity
Specific Heat Capacity
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
12 MS/m
Electrical Resistivity
0.00000008000000000001 m Ω
Superconducting Point
0.66 K
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.0000000006 m³/Kg
Magnetic Susceptibility (Molar)
0.00000000011 m³/mol
Magnetic Susceptibility (Volume)
0.000014
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
2.74 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
7 MPa
Bulk Modulus
Shear Modulus
222 GPa
Young Modulus
Poisson Ratio
0.25
Speed of Sound
4,940 m/s
Classification
CategoryTransition metals, Transition metals
CAS GroupVIIIA
IUPAC GroupVIII
Glawe Number60
Mendeleev Number61
Pettifor Number62
Geochemical Classnoble metal
Goldschmidt Classsiderophile
Other
Gas Basicity
Dipole Polarizability
57 ± 3 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
15
Neutron Mass Absorption
0.0023
Quantum Numbers5D4
Space Group194 (P63/mmc)

Isotopes of Osmium

Stable Isotopes7
Unstable Isotopes36
Radioactive Isotopes38

161Os

AbundanceRadioactive ☢️
Relative Atomic Mass
160.989054 ± 0.000429 Da
Mass Number161
G-Factor
Half Life
640 ± 60 us
Spin7/2
Quadrupole Moment
Discovery Year2010
Parity-

161Os Decay Modes
Decay ModeIntensity
α (α emission)100%

162Os

AbundanceRadioactive ☢️
Relative Atomic Mass
161.984434 ± 0.000322 Da
Mass Number162
G-Factor
0
Half Life
2.1 ± 0.1 ms
Spin0
Quadrupole Moment
0
Discovery Year1989
Parity+

162Os Decay Modes
Decay ModeIntensity
α (α emission)100%

163Os

AbundanceRadioactive ☢️
Relative Atomic Mass
162.982462 ± 0.000322 Da
Mass Number163
G-Factor
Half Life
5.7 ± 0.5 ms
Spin7/2
Quadrupole Moment
Discovery Year1981
Parity-

163Os Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

164Os

AbundanceRadioactive ☢️
Relative Atomic Mass
163.978073158 ± 0.000160927 Da
Mass Number164
G-Factor
0
Half Life
21 ± 1 ms
Spin0
Quadrupole Moment
0
Discovery Year1981
Parity+

164Os Decay Modes
Decay ModeIntensity
α (α emission)96%
β+ (β+ decay; β+ = ϵ + e+)%

165Os

AbundanceRadioactive ☢️
Relative Atomic Mass
164.976654 ± 0.000215 Da
Mass Number165
G-Factor
Half Life
71 ± 3 ms
Spin7/2
Quadrupole Moment
Discovery Year1978
Parity-

165Os Decay Modes
Decay ModeIntensity
α (α emission)90%
β+ (β+ decay; β+ = ϵ + e+)10%

166Os

AbundanceRadioactive ☢️
Relative Atomic Mass
165.972698135 ± 0.000019287 Da
Mass Number166
G-Factor
0
Half Life
213 ± 5 ms
Spin0
Quadrupole Moment
0
Discovery Year1977
Parity+

166Os Decay Modes
Decay ModeIntensity
α (α emission)83%
β+ (β+ decay; β+ = ϵ + e+)17%

167Os

AbundanceRadioactive ☢️
Relative Atomic Mass
166.971552304 ± 0.000086841 Da
Mass Number167
G-Factor
Half Life
839 ± 5 ms
Spin7/2
Quadrupole Moment
Discovery Year1977
Parity-

167Os Decay Modes
Decay ModeIntensity
α (α emission)51%
β+ (β+ decay; β+ = ϵ + e+)%

168Os

AbundanceRadioactive ☢️
Relative Atomic Mass
167.96779905 ± 0.000010631 Da
Mass Number168
G-Factor
0
Half Life
2.1 ± 0.1 s
Spin0
Quadrupole Moment
0
Discovery Year1977
Parity+

168Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)57%
α (α emission)43%

169Os

AbundanceRadioactive ☢️
Relative Atomic Mass
168.967017521 ± 0.000027847 Da
Mass Number169
G-Factor
Half Life
3.46 ± 0.11 s
Spin5/2
Quadrupole Moment
Discovery Year1972
Parity-

169Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)86.3%
α (α emission)13.7%

170Os

AbundanceRadioactive ☢️
Relative Atomic Mass
169.963579273 ± 0.000010476 Da
Mass Number170
G-Factor
0
Half Life
7.37 ± 0.18 s
Spin0
Quadrupole Moment
0
Discovery Year1972
Parity+

170Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)90.5%
α (α emission)9.5%

171Os

AbundanceRadioactive ☢️
Relative Atomic Mass
170.963180402 ± 0.000019589 Da
Mass Number171
G-Factor
Half Life
8.3 ± 0.2 s
Spin5/2
Quadrupole Moment
Discovery Year1972
Parity-

171Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
α (α emission)1.8%

172Os

AbundanceRadioactive ☢️
Relative Atomic Mass
171.960017309 ± 0.000013704 Da
Mass Number172
G-Factor
0
Half Life
19.2 ± 0.9 s
Spin0
Quadrupole Moment
0
Discovery Year1971
Parity+

172Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)98.81%
α (α emission)1.19%

173Os

AbundanceRadioactive ☢️
Relative Atomic Mass
172.959808387 ± 0.000016059 Da
Mass Number173
G-Factor
Half Life
22.4 ± 0.9 s
Spin5/2
Quadrupole Moment
Discovery Year1971
Parity-

173Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.6%
α (α emission)0.4%

174Os

AbundanceRadioactive ☢️
Relative Atomic Mass
173.957063192 ± 0.000011008 Da
Mass Number174
G-Factor
0
Half Life
44 ± 4 s
Spin0
Quadrupole Moment
0
Discovery Year1971
Parity+

174Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)0.024%

175Os

AbundanceRadioactive ☢️
Relative Atomic Mass
174.956945126 ± 0.00001264 Da
Mass Number175
G-Factor
Half Life
1.4 ± 0.1 m
Spin5/2
Quadrupole Moment
Discovery Year1972
Parity-

175Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

176Os

AbundanceRadioactive ☢️
Relative Atomic Mass
175.954770315 ± 0.000011754 Da
Mass Number176
G-Factor
0
Half Life
3.6 ± 0.5 m
Spin0
Quadrupole Moment
0
Discovery Year1970
Parity+

176Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

177Os

AbundanceRadioactive ☢️
Relative Atomic Mass
176.954957902 ± 0.000015687 Da
Mass Number177
G-Factor
Half Life
3 ± 0.2 m
Spin1/2
Quadrupole Moment
0
Discovery Year1970
Parity-

177Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

178Os

AbundanceRadioactive ☢️
Relative Atomic Mass
177.953253334 ± 0.000014634 Da
Mass Number178
G-Factor
0
Half Life
5 ± 0.4 m
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

178Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

179Os

AbundanceRadioactive ☢️
Relative Atomic Mass
178.953815985 ± 0.000016645 Da
Mass Number179
G-Factor
Half Life
6.5 ± 0.3 m
Spin1/2
Quadrupole Moment
0
Discovery Year1968
Parity-

179Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

180Os

AbundanceRadioactive ☢️
Relative Atomic Mass
179.952381665 ± 0.000016878 Da
Mass Number180
G-Factor
0
Half Life
21.5 ± 0.4 m
Spin0
Quadrupole Moment
0
Discovery Year1967
Parity+

180Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

181Os

AbundanceRadioactive ☢️
Relative Atomic Mass
180.953247188 ± 0.000027201 Da
Mass Number181
G-Factor
Half Life
105 ± 3 m
Spin1/2
Quadrupole Moment
0
Discovery Year1966
Parity-

181Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

182Os

AbundanceRadioactive ☢️
Relative Atomic Mass
181.952110154 ± 0.000023344 Da
Mass Number182
G-Factor
0
Half Life
21.84 ± 0.2 h
Spin0
Quadrupole Moment
0
Discovery Year1950
Parity+

182Os Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

183Os

AbundanceRadioactive ☢️
Relative Atomic Mass
182.953125028 ± 0.000053428 Da
Mass Number183
G-Factor
0.17644444444444 ± 0.0031111111111111
Half Life
13 ± 0.5 h
Spin9/2
Quadrupole Moment
3.1 ± 0.3
Discovery Year1950
Parity+

183Os Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

184Os

AbundanceRadioactive ☢️
0.02 ± 0.02
Relative Atomic Mass
183.952492919 ± 0.00000089 Da
Mass Number184
G-Factor
0
Half Life
11.2 ± 2.3 Ty
Spin0
Quadrupole Moment
0
Discovery Year1937
Parity+

184Os Decay Modes
Decay ModeIntensity
α (α emission)%
+ (double β+ decay)%

185Os

AbundanceRadioactive ☢️
Relative Atomic Mass
184.954045969 ± 0.000000893 Da
Mass Number185
G-Factor
Half Life
92.95 ± 0.09 d
Spin1/2
Quadrupole Moment
0
Discovery Year1947
Parity-

185Os Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

186Os

AbundanceRadioactive ☢️
1.59 ± 0.64
Relative Atomic Mass
185.953837569 ± 0.000000816 Da
Mass Number186
G-Factor
0
Half Life
2 ± 1.1 Py
Spin0
Quadrupole Moment
0
Discovery Year1931
Parity+

186Os Decay Modes
Decay ModeIntensity
α (α emission)100%

187Os

Abundance
1.96 ± 0.17
Relative Atomic Mass
186.955749569 ± 0.000000791 Da
Mass Number187
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year1931
Parity-

187Os Decay Modes
Decay ModeIntensity
α (α emission)%

188Os

Abundance
13.24 ± 0.27
Relative Atomic Mass
187.955837292 ± 0.000000788 Da
Mass Number188
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1931
Parity+

188Os Decay Modes
Decay ModeIntensity
α (α emission)%

189Os

Abundance
16.15 ± 0.23
Relative Atomic Mass
188.958145949 ± 0.000000715 Da
Mass Number189
G-Factor
Half Life
Spin3/2
Quadrupole Moment
0.86 ± 0.03
Discovery Year1931
Parity-

189Os Decay Modes
Decay ModeIntensity
α (α emission)%

190Os

Abundance
26.26 ± 0.2
Relative Atomic Mass
189.958445442 ± 0.000000697 Da
Mass Number190
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1931
Parity+

190Os Decay Modes
Decay ModeIntensity
α (α emission)%

191Os

AbundanceRadioactive ☢️
Relative Atomic Mass
190.960928105 ± 0.000000707 Da
Mass Number191
G-Factor
0.21333333333333 ± 0.0066666666666667
Half Life
14.99 ± 0.02 d
Spin9/2
Quadrupole Moment
2.53 ± 0.16
Discovery Year1940
Parity-

191Os Decay Modes
Decay ModeIntensity
β (β decay)100%

192Os

Abundance
40.78 ± 0.32
Relative Atomic Mass
191.961478765 ± 0.000002484 Da
Mass Number192
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1931
Parity+

192Os Decay Modes
Decay ModeIntensity
(double β decay)%
α (α emission)%

193Os

AbundanceRadioactive ☢️
Relative Atomic Mass
192.964149637 ± 0.00000249 Da
Mass Number193
G-Factor
0.48666666666667 ± 0.0013333333333333
Half Life
29.83 ± 0.018 h
Spin3/2
Quadrupole Moment
Discovery Year1940
Parity-

193Os Decay Modes
Decay ModeIntensity
β (β decay)100%

194Os

AbundanceRadioactive ☢️
Relative Atomic Mass
193.965179407 ± 0.000002579 Da
Mass Number194
G-Factor
0
Half Life
6 ± 0.2 y
Spin0
Quadrupole Moment
0
Discovery Year1951
Parity+

194Os Decay Modes
Decay ModeIntensity
β (β decay)100%

195Os

AbundanceRadioactive ☢️
Relative Atomic Mass
194.968318 ± 0.00006 Da
Mass Number195
G-Factor
Half Life
6.5 ± 1.1 m
Spin3/2
Quadrupole Moment
Discovery Year2004
Parity-

195Os Decay Modes
Decay ModeIntensity
β (β decay)100%

196Os

AbundanceRadioactive ☢️
Relative Atomic Mass
195.969643261 ± 0.000043 Da
Mass Number196
G-Factor
0
Half Life
34.9 ± 0.2 m
Spin0
Quadrupole Moment
0
Discovery Year1977
Parity+

196Os Decay Modes
Decay ModeIntensity
β (β decay)100%

197Os

AbundanceRadioactive ☢️
Relative Atomic Mass
196.973076 ± 0.000215 Da
Mass Number197
G-Factor
Half Life
93 ± 7 s
Spin5/2
Quadrupole Moment
Discovery Year2003
Parity-

197Os Decay Modes
Decay ModeIntensity
β (β decay)100%

198Os

AbundanceRadioactive ☢️
Relative Atomic Mass
197.974664 ± 0.000215 Da
Mass Number198
G-Factor
0
Half Life
125 ± 28 s
Spin0
Quadrupole Moment
0
Discovery Year2008
Parity+

198Os Decay Modes
Decay ModeIntensity
β (β decay)100%

199Os

AbundanceRadioactive ☢️
Relative Atomic Mass
198.978239 ± 0.000215 Da
Mass Number199
G-Factor
Half Life
6 ± 3 s
Spin5/2
Quadrupole Moment
Discovery Year2008
Parity-

199Os Decay Modes
Decay ModeIntensity
β (β decay)100%

200Os

AbundanceRadioactive ☢️
Relative Atomic Mass
199.980086 ± 0.000322 Da
Mass Number200
G-Factor
0
Half Life
7 ± 4 s
Spin0
Quadrupole Moment
0
Discovery Year2005
Parity+

200Os Decay Modes
Decay ModeIntensity
β (β decay)100%

201Os

AbundanceRadioactive ☢️
Relative Atomic Mass
200.984069 ± 0.000322 Da
Mass Number201
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year2009
Parity-

201Os Decay Modes
Decay ModeIntensity
β (β decay)%

202Os

AbundanceRadioactive ☢️
Relative Atomic Mass
201.986548 ± 0.000429 Da
Mass Number202
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year2009
Parity+

202Os Decay Modes
Decay ModeIntensity
β (β decay)%

203Os

AbundanceRadioactive ☢️
Relative Atomic Mass
202.992195 ± 0.000429 Da
Mass Number203
G-Factor
Half Life
Spin9/2
Quadrupole Moment
Discovery Year2012
Parity+

203Os Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

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
Etymology (Name Origin)Greek: osmê (odor).
PronunciationOZ-mi-em (English)
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.

Abundance
Abundance in Earth's crust
0.0015 mg/kg
Abundance in Oceans
Abundance in Human Body
Abundance in Meteor
0.000066 %
Abundance in Sun
0.0000002 %
Abundance in Universe
0.0000003 %

Nuclear Screening Constants

1s1.4701
2p4.4502
2s19.8502
3d13.5253
3p21.7483
3s22.5727
4d37.142
4f38.8472
4p34.856
4s33.9048
5d58.003
5p53.09
5s50.905
6s65.677