Chromium
Hard silvery transition element. Used in decorative electroplating. Discovered in 1797 by Vauquelin.
Gallery
Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/chromium.php
Physical Propertiesmass · density · phase · crystal
Atomic Mass
51.9961Da
Density
7.1500g/cm³
Phase (STP)
Solid
Melting Point
2180.2K
Boiling Point
2944.2K
Molar Heat
0.4490J/(mol·K)
Crystal Structure
BCC
Lattice Constant
2.880Å
Atomic Radiiatomic · covalent · van der Waals
Atomic (Empirical)
140.00pm
Covalent
122.00pm
Van der Waals
206.00pm
Electronic Propertieselectronegativity · ionization · affinity
Electron Configuration
[Ar] 3d5 4s
Electron Shells
2, 8, 13, 1
Electronegativity
1.66Pauling
Electron Affinity
0.7kJ/mol
1st Ionization Energy
6.8kJ/mol
Oxidation States
-4, -2, -1, 0, +1, +2, +3, +4, +5, +6
Orbital DiagramAufbau · Hund's rule · Pauli exclusion
Full: 1s2 2s2 2p6 3s2 3p6 3d5 4s1Short: [Ar] 3d5 4s
Ionization Energies (24 known)
Emission Spectrumvisible range · characteristic spectral lines
Abundanceby mass
Log scale · ppm = parts per million by mass
Biological Role
Enhances insulin action in glucose metabolism. Required in microgram amounts.
Discovery
Discovered By
Louis Vauquelin
Named By
—
Year
1797
Nuclear Data
Known Isotopes
30
Stable Isotopes
5
Stable Mass Numbers
41, 50, 52, 53, 54
Natural isotopic abundance (IUPAC recommended values)
Isotopes of Cr30 known
| Nuclide | Z | N | Mass (AMU) | Half-life | Decay | Jπ | Abundance |
|---|---|---|---|---|---|---|---|
| 41Crstable | 24 | 17 | 41.021911 | Stable | p | 3/2+ | — |
| 42Cr | 24 | 18 | 42.007579 | 13.3 ms | β⁺ (1%), β⁺p (0.9440000000000001%), 2p | 0+ | — |
| 43Cr | 24 | 19 | 42.997885 | 21.1 ms | β⁺ (1%), β⁺p (0.7929999999999999%), 2p (0.11599999999999999%), 3p (0.0013%), β⁺α | 3/2+ | — |
| 50Crstable | 24 | 26 | 49.946042 | Stable | 2β⁺ | 0+ | 434.5000% |
| 52Crstable | 24 | 28 | 51.940505 | Stable | stable (1%) | 0+ | 8378.9000% |
| 53Crstable | 24 | 29 | 52.940646 | Stable | stable (1%) | 3/2- | 950.1000% |
| 54Crstable | 24 | 30 | 53.938877 | Stable | stable (1%) | 0+ | 236.5000% |
| 68Cr | 24 | 44 | 67.983156 | Unknown | β⁻, β⁻n, 2n | 0+ | — |
| 69Cr | 24 | 45 | 68.989662 | Unknown | β⁻, β⁻n, 2n | 7/2+ | — |
| 70Cr | 24 | 46 | 69.993945 | Unknown | β⁻, β⁻n, 2n | 0+ | — |