Periodic Table/Osmium
← ReIr →
76Os190.2300 Da

Osmium

Transition Metal·Period 6, Group 8·s-block

Hard blue-white metallic transition element. Found with platinum and used in some alloys with platinum and iridium.

Gallery

Pure Osmium Bead

Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/osmium.php

Bohr model of Osmium

Physical Propertiesmass · density · phase · crystal

Atomic Mass

190.2300Da

Density

22.5872g/cm³

Phase (STP)

Solid

Melting Point

3306.2K

Boiling Point

5281.1K

Molar Heat

0.1300J/(mol·K)

Crystal Structure

HEX

Lattice Constant

2.740Å

Atomic Radiiatomic · covalent · van der Waals

Atomic (Empirical)

130.00pm

Covalent

129.00pm

Van der Waals

216.00pm

Electronic Propertieselectronegativity · ionization · affinity

Electron Configuration

[Xe] 4f14 5d6 6s2

Electron Shells

2, 8, 18, 32, 14, 2

Electronegativity

2.20Pauling

Electron Affinity

1.1kJ/mol

1st Ionization Energy

8.4kJ/mol

Oxidation States

-4, -2, -1, 0, +1, +2, +3, +4, +5, +6, +7, +8

Orbital DiagramAufbau · Hund's rule · Pauli exclusion

↑↓
1s2
↑↓
2s2
↑↓
↑↓
↑↓
2p6
↑↓
3s2
↑↓
↑↓
↑↓
3p6
↑↓
↑↓
↑↓
↑↓
↑↓
3d10
↑↓
4s2
↑↓
↑↓
↑↓
4p6
↑↓
↑↓
↑↓
↑↓
↑↓
4d10
↑↓
5s2
↑↓
↑↓
↑↓
5p6
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
4f14
↑↓
↑
↑
↑
↑
5d6
↑↓
6s2

Full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d6 6s2Short: [Xe] 4f14 5d6 6s2

Ionization Energies (76 known)

1st8.4 kJ/mol2nd17.0 kJ/mol3rd25.0 kJ/mol4th41.0 kJ/mol5th55.0 kJ/mol6th70.1 kJ/mol7th85.1 kJ/mol8th102.0 kJ/mol9th168.7 kJ/mol10th190.0 kJ/mol11th213.0 kJ/mol12th235.0 kJ/mol13th269.0 kJ/mol14th298.0 kJ/mol15th322.0 kJ/mol16th367.0 kJ/mol17th410.0 kJ/mol18th436.0 kJ/mol19th470.0 kJ/mol20th520.0 kJ/mol21th570.0 kJ/mol22th620.0 kJ/mol23th670.0 kJ/mol24th720.0 kJ/mol25th770.0 kJ/mol26th820.0 kJ/mol27th870.0 kJ/mol28th920.0 kJ/mol29th970.0 kJ/mol30th1015.0 kJ/mol31th1262.0 kJ/mol32th1311.0 kJ/mol33th1364.0 kJ/mol34th1420.0 kJ/mol35th1474.0 kJ/mol36th1528.0 kJ/mol37th1606.0 kJ/mol38th1660.0 kJ/mol39th1720.0 kJ/mol40th1776.0 kJ/mol41th1996.0 kJ/mol42th2052.0 kJ/mol43th2112.0 kJ/mol44th2168.0 kJ/mol45th2336.0 kJ/mol46th2400.0 kJ/mol47th2552.0 kJ/mol48th2615.5 kJ/mol49th4374.0 kJ/mol50th4501.0 kJ/mol51th4635.0 kJ/mol52th4779.0 kJ/mol53th4917.0 kJ/mol54th5052.0 kJ/mol55th5280.0 kJ/mol56th5421.0 kJ/mol57th5575.0 kJ/mol58th5717.0 kJ/mol59th6115.0 kJ/mol60th6240.0 kJ/mol61th6376.0 kJ/mol62th6503.0 kJ/mol63th7039.0 kJ/mol64th7185.0 kJ/mol65th7468.0 kJ/mol66th7610.0 kJ/mol67th16560.0 kJ/mol68th16900.0 kJ/mol69th17270.0 kJ/mol70th17620.0 kJ/mol71th19600.0 kJ/mol72th20030.0 kJ/mol73th20570.0 kJ/mol74th20920.6 kJ/mol75th83976.2 kJ/mol76th85614.4 kJ/molSuccessive Ionization Energies

Emission Spectrumvisible range · characteristic spectral lines

442
426
430
Os emission
380nm750nm
426.1 nm(100%)442.0 nm(50%)430.0 nm(40%)

Abundanceby mass

🌍Earth's Crust
1.5 ppb
🌊Ocean—
✨Universe
3.0 ppb
🧬Human Body—

Log scale · ppm = parts per million by mass

Biological Role

Toxic

Osmium tetroxide (OsO₄) is highly toxic and a powerful oxidizer. Metal form is less dangerous.

Discovery

Discovered By

Smithson Tenant

Named By

—

Year

1804

Nuclear Data

Known Isotopes

43

Stable Isotopes

5

Stable Mass Numbers

187, 188, 189, 190, 192

Natural isotopic abundance (IUPAC recommended values)

Isotopes of Os43 known

NuclideZNMass (AMU)Half-lifeDecayJπAbundance
161Os7685160.989054640 μsα (1%)7/2-—
162Os7686161.9844342.10 msα (1%)0+—
163Os7687162.9824625.70 msα (1%), β⁺7/2-—
184Os76108183.95249311200 Gyα, 2β⁺0+2.0000%
186Os76110185.9538382000000 Gyα (1%)0+159.0000%
187Osstable76111186.955750Stableα1/2-196.0000%
188Osstable76112187.955837Stableα0+1324.0000%
189Osstable76113188.958146Stableα3/2-1615.0000%
190Osstable76114189.958445Stableα0+2626.0000%
192Osstable76116191.961479Stable2β⁻, α0+4078.0000%
201Os76125200.984069Unknownβ⁻1/2-—
202Os76126201.986548Unknownβ⁻0+—
203Os76127202.992195Unknownβ⁻, β⁻n9/2+—

Click any isotope for its full page with decay chain:

161Os162Os163Os164Os165Os166Os167Os168Os169Os170Os171Os172Os173Os174Os175Os176Os177Os178Os179Os180Os181Os182Os183Os184Os185Os186Os187Os188Os189Os190Os191Os192Os193Os194Os195Os196Os197Os198Os199Os200Os201Os202Os203Os
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