About

Scandium is a silvery-white transition metal that is relatively soft. While not abundant, adding small amounts of scandium to aluminum alloys creates materials that are exceptionally strong, lightweight, and durable. These high-performance alloys are used in specialized applications like aerospace components, high-end bicycle frames, and baseball bats. It is named after Scandinavia.

Atomic Properties

Atomic Number21

Atomic Weight44.956 u

Neutrons (common)24

Electron Configuration[Ar] 3d¹ 4s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹ 4s²

Electrons per Shell2, 8, 9, 2

Electronegativity1.36

Electron Affinity18.1 kJ/mol

Oxidation States+3

Covalent Radius144 pm

Ionic Radius74.5 pm

Periodic Table Position

Group3

Period4

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

Appearancesilvery white

Crystal Structurehcp

Magnetic Orderingparamagnetic

Speed of Sound1,600 m/s

Poisson Ratio0.279

Thermal Properties

Melting Point1,814 K

Boiling Point3,109 K

Thermal Expansion10.2 1/K

Thermal Conductivity15.8 W/(m·K)

Specific Heat0.568 J/(g·K)

Molar Heat25.52 J/(mol·K)

Heat of Fusion14.1 kJ/mol

Heat of Vaporization332.7 kJ/mol

Abundance

In Earth's Crust22 ppm

In Ocean0 ppm

In Solar System0.012 ppm

In Universe0.03 ppm

Discovery

Discovered byLars Fredrik Nilson

Discovery Year1,879

Occurrenceprimordial

CAS Number7440-20-2

Electron Configuration

Energy

↿⇂

↿

Isotopes of Scandium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
⁴⁴Sc	43.959403	—	4.042 h	Positron Emission
⁴⁴Sc	44.959403	—	58.61 h	Internal Transition
⁴⁵Sc	44.955912	100%	Stable	Stable
⁴⁶Sc	45.955172	—	83.79 d	Beta Minus Decay
⁴⁷Sc	46.952408	—	3.3492 d	Beta Minus Decay
⁴⁸Sc	47.952231	—	43.67 h	Beta Minus Decay

Interactive Visualization

Explore the 3D Bohr model of Scandium in our interactive viewer.

View 3D Model of Scandium