Antimony (Sb)

Silvery-gray metalloid

Antimony is a brittle metalloid used in flame retardants, lead-acid batteries, and semiconductors, and with a half-filled 5p³ shell, antimony has a metallic form (silvery, rhombohedral) and a non-metallic form (yellow, polyatomic). Antimony trioxide is the most widely used flame retardant synergist.

Key metrics

Density6.68g/cm³

Melting point904K

Boiling point1,860K

Electronegativity2.05Pauling

Discovery

-1600discovered

Discovered by: Ancient civilizations
Reactivity profile: Brittle and toxic
Reactivity: Medium
Bonding: Covalent

Electron configuration

\textcolor{#6b7280}{[Kr]}\; \textcolor{#22c55e}{4_{d}^{10}}\; \textcolor{#ef4444}{5_{s}^{2}}\; \textcolor{#3b82f6}{5_{p}^{3}}

[Kr] 4d10 5s2 5p3

Wave function

\Psi_{\text{Sb}} \approx \frac{1}{\sqrt{51!}} \det \left| \chi_1(\mathbf{r}_1) \dots \chi_{51}(\mathbf{r}_{51}) \right|

Probability density $|\Psi|^2$ across the Sb valence shell.

Crystal structure

Rhombohedral

Lattice constantsa 1.00 · b 1.00 · c 1.00

Cell anglesα = β = γ = 61.5°

Coordination number—

Atoms per cell—

Atomic packing factor0.53

Physical properties

Atomic radius: 133 pm
Ionization energy: 834 kJ/mol
Electron affinity: 101 kJ/mol
Crystal structure: Rhombohedral

Oxidation states

-3+3+5

Acid/base

Can act as acid or base

Strongly acidicStrongly basic

State at 25 °CSolid

904 K1860 K298 K

Emission spectrum

3 transitions

380450500550600650700780

VioletBlueGreenYellowRed

464.1nmSb I (blue)Blue100%

478.9nmSb IBlue50%

503.8nmSb I (green)Cyan60%

Dominant line 464.1 nmRange 464–504 nmTransitions 3