ElementsWhat is chromium?
Chromium is a hard, shiny, steel-grey metal that takes a mirror polish and does not tarnish. Rubies are red and emeralds green because of traces of chromium.
What is chromium used for?
Stainless steel, shiny chrome plating on taps and car parts, pigments, and leather tanning.
Where the name comes from
From the Greek word chroma, colour, because its compounds are brightly coloured.
Key facts
- Symbol
- Cr
- Atomic number
- 24
- Atomic mass
- 51.996 u
- Family
- Transition metal
- Period
- 4
- Group
- 6
- Block
- d
- State at room temperature
- Solid
- Melting point
- 1,907 °C (2,180 K, 3,464 °F)
- Boiling point
- 2,671 °C (2,944 K, 4,840 °F)
- Density
- 7.15 g/cm³
- Electrons per shell
- 2, 8, 13, 1
- Electron configuration
- [Ar]3d5 4s1
- Common oxidation states
- +6, +3, +2
- Electronegativity (Pauling)
- 1.66
- First ionisation energy
- 6.767 eV
- Electron affinity
- 0.666 eV
- Atomic radius (van der Waals)
- 189 pm
- Discovered
- 1797
Place in the periodic table
Chromium is element number 24. It sits in period 4 (row 4) of the periodic table, in group 6 (column 6), and belongs to the d-block. Just before it comes vanadium (23), and just after it comes manganese (25). In the same column, molybdenum is below it. Elements in one column tend to behave alike.
Family: Transition metals.
Physical properties
At room temperature chromium is a solid. It melts at 1,907 °C and boils at 2,671 °C, so it stays liquid over a range of 764 degrees. Its density is 7.15 grams per cubic centimetre, so a one-litre block would weigh about 7.15 kilograms. By density it ranks 47th among the 96 elements with a measured value.
Inside the atom
An atom of chromium has 24 protons in its nucleus and, when neutral, 24 electrons around it. The electrons are arranged in 4 shells: 2, 8, 13, 1. The outermost shell holds 1 electron. Written in full, the electron configuration is [Ar]3d5 4s1.
Its electronegativity on the Pauling scale is 1.66. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 6.767 electronvolts (about 653 kilojoules per mole). One mole of chromium weighs 51.996 grams, so a single gram contains about 1.16 × 1022 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains chromium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.