Curium

Element 96 · Actinide

Specimen

Atomic number
96
Atomic mass
[247]
State at room temperature
Solid
Melting point
1,345 °C
Boiling point
3,127 °C
Density
13.51 g/cm³
Discovered
1944

Mass number of the longest-lived isotope, from IUPAC.1 Other physical data from PubChem.2

Can I eat it?

In food and water
Radioactive. All curium is radioactive. Nuclear reactors make a few grams each year. Its radiation is the main danger. 3

See every element.

The atom

Cm
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) 32
5 (O) 25
6 (P) 9
7 (Q) outermost 2
Total96

Configuration [Rn] 5f⁷ 6d¹ 7s²

5f ↑ ↑ ↑ ↑ ↑ ↑ ↑
6d ↑
7s ↑ ↓
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 96 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 Rn core, with one arrow per electron.

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Radioactive Elements .

    Mass number and half-life of the longest-lived isotope of the 34 elements with no 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

    Royal Society of Chemistry, Periodic Table, 2026. Curium - Element information, properties and uses .

    Reference page; its Biological role and Natural abundance sections are quoted.

    • Curium has no known biological role. It is toxic due to its radioactivity. ... Only a few grams are produced each year.