Chromium
Chromium (铬, symbol Cr) is chemical element number 24, a Transition Metal in period 4, group 6 of the periodic table, with a standard atomic weight of about 51.996. Lustrous, hard, brittle metal. Provides corrosion resistance in stainless steel.
Properties
| Atomic number | 24 |
|---|---|
| Symbol | Cr |
| Atomic mass | 51.996 u |
| Category | Transition Metal |
| Period | 4 |
| Group | 6 |
| Electron configuration | [Ar] 3d⁵ 4s¹ |
| Electronegativity | 1.66 |
| Covalent radius | 139 pm |
| Density | 7.15 g/cm³ |
| Melting point | 2180 K |
| Boiling point | 2944 K |
| Discovery | Louis Nicolas Vauquelin, 1797 |
Overview
Lustrous, hard, brittle metal. Provides corrosion resistance in stainless steel. Chromium (symbol Cr) is chemical element number 24, sitting in period 4, group 6 of the periodic table and classed as a Transition Metal. As a transition metal it commonly shows several oxidation states, forms coloured compounds, and is widely used in catalysts and alloys.
It has the configuration [Ar] 3d⁵ 4s¹ and an electronegativity near 1.66; its 1 outer-shell electron drives its bonding. Under standard conditions it exists as a solid (a very high melting point); it melts near 2180 K (1906.9 °C), boils near 2944 K (2670.9 °C), has a density around 7.15 g/cm³.
It is widely used in Structural / Alloys and Pigments / Glass. It is regarded as a moderate-hazard element, so handle it with appropriate care. It was first described by Louis Nicolas Vauquelin in 1797. The periodic trends guide explains the underlying patterns.
Electron shells
Electrons per shell: 2 · 8 · 13 · 1
Main uses
- Structural / Alloys
- Pigments / Glass
Hazard
Compounds containing Chromium
No compounds in this knowledge base contain Chromium yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.