51 Sb 121.76

Antimony

Metalloid

Antimony (Sb) is a chemical element with atomic number 51, classified as a metalloid. At room temperature it is a solid. It has been known since ancient times.

Properties

Atomic number
51
Atomic mass
121.76 u
Category
Metalloid
Group
15
Period
5
Block
p-block
Electron configuration
[Kr] 4d¹⁰ 5s² 5p³
Phase at STP
Solid
Density
6.685 g/cm³
Melting point
903.78 K (630.6 °C)
Boiling point
1860 K (1586.8 °C)
Electronegativity
2.05
Atomic radius
133 pm
Ionization energy
8.608 eV
Discovery
Known since ancient times

Common uses

Flame retardants, semiconductors, batteries, pewter

Did you know?

Used in ancient times as eye makeup and now in flame-retardant materials.