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Chromium

Element 24 · Transition metal

Specimen

Atomic number
24
Atomic mass
51.996
State at room temperature
Solid
Melting point
1,907 °C
Boiling point
2,671 °C
Density
7.15 g/cm³
Discovered
1797

Atomic mass from IUPAC.1 Other physical data from PubChem.2

Can I eat it?

In food and water
Your body needs it. The US sets a Daily Value of 35 µg of chromium for food labels. In 2014, EFSA found no benefit from chromium in healthy people, and set no intake. Chromium(VI) in drinking water is a concern for infants, according to EFSA. 345

See every element.

The atom

Cr
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 13
4 (N) outermost 1
Total24

Configuration [Ar] 3d⁵ 4s¹

3d ↑ ↑ ↑ ↑ ↑
4s ↑
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 24 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Ar core, with one arrow per electron.

Related elements

Group 6
Mo Molybdenum W Tungsten Sg Seaborgium

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Abridged Standard Atomic Weights 2024 .

    The atomic mass shown for the 84 elements that have a standard atomic weight.

  2. 2

    National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    U.S. Food and Drug Administration, 2024. Daily Value on the Nutrition and Supplement Facts Labels , Reference Guide table.

    • Chromium 35mcg
  4. 4

    European Food Safety Authority (EFSA), 2017. Dietary Reference Values for nutrients. Summary report (amended 2019) .

    Summaries of the EFSA NDA Panel opinions on each vitamin and mineral, section 4 (minerals) and section 5 (cobalamin).

    • there is no evidence of beneficial effects associated with chromium intake in healthy subjects. The Panel concludes that the setting of an Adequate Intake for chromium is also not appropriate.
  5. 5

    European Food Safety Authority (EFSA), 2025. Metals as contaminants in food , Milestones, 2014 (chromium) and 2020 (nickel).

    • there is a concern regarding average chromium VI intake via drinking water for infants
  6. 6

    National Institute of Standards and Technology (NIST), 2026. Atomic Weights and Isotopic Compositions for All Elements .

    Isotopic composition of each element; the most abundant isotope sets the neutron count in the nucleus view.