Chromium (Cr)
Chromium (Cr) is element 24 of the periodic table, a transition metal in period 4 and group 6. Its standard atomic weight is 51.9961, so one mole of chromium atoms has a mass of 51.9961 g. At room temperature it is a solid; it melts at 1906.85 °C and boils at 2670.85 °C.
| Atomic number | 24 |
|---|---|
| Symbol | Cr |
| Standard atomic weight | 51.9961 |
| Molar mass | 51.9961 g/mol |
| Category | Transition metal |
| Group | 6 |
| Period | 4 |
| Block | d-block |
| Electron configuration | [Ar] 3d5 4s1 |
| Oxidation states | +6, +3, +2 |
| Electronegativity (Pauling) | 1.66 |
| Atomic radius (van der Waals) | 189 pm |
| First ionisation energy | 6.767 eV (652.9 kJ/mol) |
| Electron affinity | 0.666 eV |
| State at room temperature | Solid |
| Melting point | 2180 K (1906.85 °C) |
| Boiling point | 2944 K (2670.85 °C) |
| Density | 7.15 g/cm³ |
| Discovered | 1797 |
Group 6
Calculate with Chromium
Atomic weight: IUPAC CIAAW standard atomic weight. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.