Scandium

01 / A closer look

Meet Scandium

Scandium has atomic number 21: every atom of this element contains 21 protons. It belongs to period 4, group 3 of the periodic table.

In a neutral atom, the number of electrons equals the number of protons. Isotopes of this element share the same atomic number but have different neutron counts.

02 / Physical properties

Melting point

1814 K

Boiling point

3109 K

Density

2.99 g/cm³

Atomic weight

44.956 ± 0.001

Melting points, boiling points and densities follow RSC fact boxes. Density is referenced to room temperature; consult the source for pressure and allotrope details. These are reference values, not a claim that every value was experimentally measured. Atomic weights follow CIAAW.

Physical-property source: Royal Society of Chemistry ↗ · Reviewed 24 September 2026

Standard atomic weights follow CIAAW 2024 (abridged). Brackets show an isotope mass number from IUPAC 2022, not a standard atomic weight.

03 / Atomic structure

Atomic structure

Electron configuration

[Ar]4s2 3d1

Oxidation states

+3

Electronegativity · Pauling

1.36

First ionisation energy

6.561 eV

Atomic radius

211 pm

04 / Where it is found

Where it is found

Dispersed through many minerals; thortveitite is a notable example.

Production and export figures depend on the commodity and reporting year. No comparable country quantities have been included for this element in this edition.