51
Sb
Antimony
121.76
Antimony (Sb)
MetalloidGroup 15Period 5p-block-block
Antimony is a chemical element with symbol Sb (from Latin:stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times and were used for cosmetics; metallic antimony was also known, but it was erroneously identified as lead upon its discovery.
Latin name: Stibium
Atomic Number
51
Atomic Mass
121.76 g/mol
Phase (STP)
Solid
Electron Config.
[Kr] 4d¹⁰ 5s² 5p³
General
SymbolSb
Atomic Number51
Atomic Mass121.76 g/mol
CategoryMetalloid
Group15
Period5
Blockp-block
Electron Configuration[Kr] 4d¹⁰ 5s² 5p³
Valence Electrons15
Coloursilvery-gray metallic
Appearancesilvery lustrous gray
CAS NumberCAS7440-36-0
Physical Properties
Phase (STP)Solid
Density6.697 g/cm³
Melting Point630.63°C · 1167.13°F · 903.78 K
Boiling Point1586.85°C · 2888.33°F · 1860.00 K
Atomic Properties
Atomic Radius133 pm
Electronegativity2.05 Pauling
Ionization Energy834 kJ/mol
Oxidation States+5, +3, -3
Ion ChargeSb3-/Sb3+/Sb5+
Thermodynamic
Molar Heat25.23 J/(mol·K)
Crystal Structure
Crystal Structurerhombohedral
Mechanical Properties
Mohs Hardness3
Abundance
In Universe0.00004%
In Sun0.00003%
In Earth's Crust0.0020%
Discovery & History
Discovered Byunknown
Isotopes of Antimony
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Sb-121 | 57.21% | Stable | — |
| Sb-123 | 42.79% | Stable | — |