Sb
Antimony
Element 51 · Metalloid
Antimony (Sb)
Antimony is a brittle, silvery metalloid. It is used mainly as a flame retardant and to harden lead.
- Metalloid
- Period 5
- Group 15
- p-block
- solid at room temperature
Key properties
- Atomic mass
- 121.76
- u
- Electron configuration
- [Kr] 4d10 5s2 5p3
- Melting point
- 630.6 °C
- 903.78 K
- Boiling point
- 1,586.9 °C
- 1,860 K
- Density
- 6.685 g/cm³
- Electronegativity
- 2.05
- Pauling
- Atomic radius
- 206 pm
- van der Waals
- 1st ionisation energy
- 8.64 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about antimony
- 01
Ancient Egyptian women used antimony sulfide (kohl) as eye makeup.
- 02
Antimony expands slightly as it solidifies, which made it ideal for casting printing type.
- 03
Antimony cups were once used as a purgative — wine left in them became an emetic.
Applications
What is antimony used for?
- Flame retardants
- Lead-acid battery alloys
- Semiconductors
- Ammunition
History
Discovery & name origin
Discovered by
Known since antiquity
Year
c. 3000 BCE
Where
Known since antiquity
Name origin
Possibly Greek anti + monos, “not alone”; the symbol Sb comes from Latin stibium.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 51
- Atomic mass
- 121.76 u
- Group
- 15
- Period
- 5
- Block
- p-block
- Electron configuration
- [Kr] 4d10 5s2 5p3
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3
- Electrons per shell
- 2, 8, 18, 18, 5
- Electronegativity (Pauling)
- 2.05
- Electron affinity
- 1.07 eV
- Atomic radius (van der Waals)
- 206 pm
- Stable isotopes
- 2
Oxidation states
Highlighted: common oxidation states (+5, +3, -3).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st834
- 2nd1,594.9
- 3rd2,440
- 4th4,260
- 5th5,400
- 6th10,400
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 903.78 K · 630.6 °C · 1,167.1 °F
- Boiling point
- 1,860 K · 1,586.9 °C · 2,888.3 °F
- Density
- 6.685 g/cm³
- Molar heat capacity
- 25.23 J/(mol·K)
- Appearance
- Silvery lustrous grey
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Antimony questions
What is Sb on the periodic table?
Sb is the symbol for antimony, element 51 on the periodic table. It sits in group 15, period 5, in the metalloid category, and has an atomic mass of 121.76.
What is the atomic number of antimony?
Antimony has atomic number 51, so every antimony atom has 51 protons in its nucleus. Its symbol is Sb and its atomic mass is 121.76.
Who discovered antimony?
Antimony has been known since antiquity (c. 3000 BCE); no single discoverer is credited. The name comes from possibly Greek anti + monos, “not alone”; the symbol Sb comes from Latin stibium.
What is antimony used for?
Antimony is used for: flame retardants; lead-acid battery alloys; semiconductors; ammunition.
Is antimony a metal?
No. Antimony is classed as a metalloid, with properties between metals and nonmetals.
What is the electron configuration of antimony?
The electron configuration of antimony is [Kr] 4d10 5s2 5p3. Its 51 electrons are arranged in shells as 2, 8, 18, 18, 5.