Chromium is named after chroma, the Greek word meaning "color". Many chromium minerals, including chromite and chrocoite, are brightly colored. An artificial form of crocoite, known as "chromium yellow", was used in paints, but was banned due to the toxicity of chromium salts. Pure chromium does not corrode easily, so it is combined with carbon oxide and carbon to produce stainless steel. Chromium also gives gemstones, such as rubies, their deep red color. Chrome-plated bodywork and parts are also used in vehicles, giving them a shiny finish.
Summary of properties (Cr)
| Atomic weight | 51.9961(6) |
| Discoverer (year) | Vauquelin (1797) |
| Natural form | metallic solid (body centered cubic) |
| Electron configuration | [Ar] 3d5 4s1 |
| Melting point (ºC) | 1857 |
| Boiling point (ºC) | 2672 |
| Abundance in earth's crust (ppm) | 102 |
| Isotope (abundance) | 50Cr (4.345), 52Cr (83.789), 53Cr (9.501), 54Cr (2.365) |
| Density g/cm3 | 7.19 |
| Van der Waals radius (pm) | 206 |
| Covalent radius (pm) | 130 |
| Electronegativity (Pauling) | 1.55 |
| Vaporization enthalpy (kJ/mol) | 348.80 |
| Enthalpy of fusion (kJ/mol) | 21.00 |
| Specific heat capacity (J/g·K) at 25ºC and 1 atm | 0.45 |
| Thermal conductivity (W/cm·K) at 25ºC and 1 atm | 0.940 |
| Oxidation state | +6, +3, +2 |
| Electron affinity (eV) | 0.67 |
| 1st Ionization potential (eV) | 6.7665 |
