Osmium

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Osmium Quick Reference

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Notes

Symbol

Os

Atomic Number

76

Atomic Weight

Rounded

190.2

for regular calculations

Standard

190.23 ± 0.03

for precise calculations

Oxidation States

 8

less common with disagreement

 7

less common

 6

less common with disagreement

 5

less common

 4

more common

 3

less common

 2

less common

 1

less common

 0

less common

-2

less common

Pauling Electronegativity

2.2

Electron Configuration

Orbital Occupancy

[Xe] 4f14 5d6 6s2

[Xe] represents the closed-shell electron configuration of xenon

Orbital Filling Order

[Xe] 6s2 4f14 5d6

[Xe] represents the closed-shell electron configuration of xenon

Term Symbol

5D4

see expanded configuration ...

Ionization Energies

I (1)

8.43823 eV

Electron Affinity

1.07780 ± 0.00012 eV

   8693 ± 1 cm-1    

Density

liquid, 3306.15 K

20.100 g/ml 

solid

25 °C

22.590 g/cm3

20 °C

22.587 ± 0.009 g/cm3

densest metal at 20 °C

Molar Volume

solid, 298 K, 1 atm

8.42 cm3/mol

Melting Point

1 atm

3400 ± 50 K

Boiling Point

1 atm

5576 ± 30 K

reference stated that the uncertainty may be larger than indicated

Thermal Conductivity

solid

400 K, polycrystalline

86.9 W/(m K)

300 K, polycrystalline

87.6 W/(m K)

extrapolated or interpolated

298.2 K, polycrystalline

87.6 W/(m K)

extrapolated or interpolated

273.2 K, polycrystalline

88.0 W/(m K)

extrapolated or interpolated

200 K, polycrystalline

90.8 W/(m K)

extrapolated or interpolated

see all 43 conductivities ...

Pyykkö Covalent Radius

single bond

129 pm

double bond

116 pm

triple bond

109 pm

Atomic Radius

135 pm

Enthalpy of Fusion

1 atm

29.3 kJ/mol

Enthalpy of Vaporization

1 atm

627.6 kJ/mol

Quantity

Osmium Atomic Structure

Notes

Ionization Energies

I (1)

8.43823 eV

Electron Affinity

1.07780 ± 0.00012 eV

   8693 ± 1 cm-1    

Electron Binding Energies

K    (1s)

73871 eV  

LI   (2s)

12968 eV  

LII  (2p1/2)

12385 eV  

LIII (2p3/2)

10871 eV  

see all 19 energies ...

Electron Configuration

Orbital Occupancy

[Xe] 4f14 5d6 6s2

[Xe] represents the closed-shell electron configuration of xenon

Orbital Filling Order

[Xe] 6s2 4f14 5d6

[Xe] represents the closed-shell electron configuration of xenon

Term Symbol

5D4

see expanded configuration ...

Clementi-Raimondi Effective Nuclear Charge

1s

Orbital Exponent

74.5299

ζ

Principle Quantum Number

1

n

Effective Nuclear Charge

74.5299

Zeff = ζ × n

2s

Orbital Exponent

28.0749

ζ

Principle Quantum Number

2

n

Effective Nuclear Charge

56.1498

Zeff = ζ × n

see all 14 effective nuclear charges ...

Screening Percentage

86.6%

Fluorescence Yields

ωK

0.957

ωL1

0.15 

ωL2

0.318

ωL3

0.282

Coster-Kronig Yields

F12

0.07 

F13

0.482

F23

0.13 

Quantity

Osmium Physical Properties

Notes

Density

liquid, 3306.15 K

20.100 g/ml 

solid

25 °C

22.590 g/cm3

20 °C

22.587 ± 0.009 g/cm3

densest metal at 20 °C

Molar Mass

Rounded

190.2 g/mol

for regular calculations

Standard

190.23 ± 0.03 g/mol

for precise calculations

Molar Volume

solid, 298 K, 1 atm

8.42 cm3/mol

Physical Form

blue-white metal

Linear Thermal Expansion Coefficient

25 °C

5.1×10-6 K-1

Speed of Sound

solid, 293 K

4940 m/s

calculated value

Young's Modulus

558.6 GPa

Poisson's Ratio

0.250

Electrical Resistivity

solid, 295 K

9.1×10-8 Ohm m

Contact Potential

4.55 eV

Superconducting Transition Temperature

ambient pressure

0.655 K

0 Pa

0.655 K

Superconducting Critical Magnetic Field at Absolute Zero

65×10-4 T

Mineralogical Hardness

7.0

Isothermal Bulk Modulus

300 K

418 GPa

estimated

Isothermal Compressibility

300 K

0.0024 GPa-1

estimated

Gram Atomic Volume

9 cm3

Quantity

Osmium Atomic Interaction

Notes

Oxidation States

 8

less common with disagreement

 7

less common

 6

less common with disagreement

 5

less common

 4

more common

 3

less common

 2

less common

 1

less common

 0

less common

-2

less common

Pauling Electronegativity

2.2

Allred-Rochow Electronegativity

1.52

Configuration Energy

electron volt units

9.78 eV

Pauling units

1.65   

Nagle Electronegativity

1.39

Pearson Absolute Electronegativity

4.9 eV

Chemical Hardness

3.8 eV

Cohesive Energy

per mole

788 kJ/mol    

per atom

  8.17 eV/atom

Quantity

Osmium Thermodynamics

Notes

Melting Point

1 atm

3400 ± 50 K

Boiling Point

1 atm

5576 ± 30 K

reference stated that the uncertainty may be larger than indicated

Thermal Conductivity

solid

400 K, polycrystalline

86.9 W/(m K)

300 K, polycrystalline

87.6 W/(m K)

extrapolated or interpolated

298.2 K, polycrystalline

87.6 W/(m K)

extrapolated or interpolated

273.2 K, polycrystalline

88.0 W/(m K)

extrapolated or interpolated

200 K, polycrystalline

90.8 W/(m K)

extrapolated or interpolated

see all 43 conductivities ...

Critical Point

12700 K

Vapor Pressure

5576 K

1 atm

5571 K

1 bar

4810 K

1×10-1 bar

4239 K

1×10-2 bar

3400 K

7.753×10-5 bar

melting point

see all 19 pressures ...

Enthalpy of Fusion

1 atm

29.3 kJ/mol

Enthalpy of Vaporization

1 atm

627.6 kJ/mol

Isobaric Molar Heat Capacity

298.15 K, 1 bar

24.7 J/(mol K)

Isobaric Specific Heat Capacity

298.15 K, 1 bar

0.130 J/(g K)

Electronic Heat Capacity Coefficient

2.05 mJ/(mol K2)

Debye Temperature

Low Temperature Limit ( 0 K )

467 K

Room Temperature ( 298 K )

400 K

Quantity

Osmium Identification

Notes

CAS Number

7440-04-2

Quantity

Osmium Atomic Size

Notes

Atomic Radius

135 pm

Orbital Radius

126.6 pm

Pyykkö Covalent Radius

single bond

129 pm

double bond

116 pm

triple bond

109 pm

Cordero Covalent Radius

144 pm

Shannon-Prewitt Crystal Radius

ion charge: +4, coordination number: 6

77.0 pm

ion charge: +5, coordination number: 6

71.5 pm

ion charge: +6

coordination number: 5

63 pm  

coordination number: 6

68.5 pm

ion charge: +7, coordination number: 6

66.5 pm

ion charge: +8, coordination number: 4

53 pm  

Shannon-Prewitt Effective Ionic Radius

ion charge: +4, coordination number: 6

63.0 pm

ion charge: +5, coordination number: 6

57.5 pm

ion charge: +6

coordination number: 5

49 pm  

coordination number: 6

54.5 pm

ion charge: +7, coordination number: 6

52.5 pm

ion charge: +8, coordination number: 4

39 pm  

Batsanov Crystallographic Van Der Waals Radius

2.0×102 pm

Batsanov Equilibrium Van Der Waals Radius

233 pm

Slater Atomic-Ionic Radius

130 pm

Quantity

Osmium Crystal Structure

Notes

Nearest Neighbor Distance

300 K, 1 atm

268 pm

Atomic Concentration

300 K, 1 atm

7.14×1022 cm-3

Quantity

Osmium History

Notes

Discovery

date of discovery

1804

discoverer

Smithson Tennant

birth

November 30, 1761

death

February 22, 1815

location of discovery

London, England

Origin of Element Name

origin

osme

origin description

property—Greek for odor or smell

Origin of Element Symbol

symbol: Os

origin

osmium

origin description

element name

Quantity

Osmium Abundances

Notes

Earth's Crust

1.5×10-3 ppm

Earth's Mantle

3.4 ppb

primitive mantle

Earth's Core

2.8 ppm

Bulk Earth

0.9 ppm

U.S. Coal

<0.001 ppm

estimated from USGS and literature data

Solar System

0.675

number of atoms for every 106 atoms of silicon

Sun

1.45 ± 0.10

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Meteorites

1.38 ± 0.02

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Quantity

Osmium Nomenclature

Notes

Element Names in Other Languages

French

osmium

German

Osmium

Italian

osmio

Spanish

osmio

Portuguese

osmio

Anions or Anionic Substituent Groups

osmide

Cations or Cationic Substituent Groups

osmium

Ligands

osmido

Heteroatomic Anion

osmate

'a' Term—Substitutive Nomenclature

osma

'y' Term—Chains and Rings Nomenclature

osmy

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