Antimony (Sb)
Antimony is element 51, a metalloid in period 5, group 15 of the periodic table. At room temperature it is a solid.
Electron configuration [Kr] 4d10 5s2 5p3
Electrons per shell 2, 8, 18, 18, 5
Antimony data
| Atomic number | 51 |
|---|---|
| Symbol | Sb |
| Atomic mass | 121.76 u |
| Category | Metalloid |
| Group | 15 |
| Period | 5 |
| Block | p |
| State at 25 °C | solid |
| Melting point | 904 K (630.9 °C) |
| Boiling point | 1860 K (1586.9 °C) |
| Density | 6.697 g/cm³ |
| Electronegativity (Pauling) | 2.05 |
| Atomic radius | 138 pm |
| 1st ionization energy | 834 kJ/mol |
| Electron affinity | -103 kJ/mol |
| Oxidation states | -3, +3, +5 |
| Common ion charge | 3+, 5+ |
| Discovered | Known since antiquity |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through antimony’s configuration and its ions →
Where antimony sits
Antimony belongs to the metalloids. Its Pauling electronegativity of 2.05 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Antimony FAQ
What is the electron configuration of antimony?
Antimony (Z = 51) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3. In noble-gas shorthand that is [Kr] 4d10 5s2 5p3.
How many valence electrons does antimony have?
5 (outer shell (n = 5)).
What is the atomic mass of antimony?
The standard atomic weight of antimony is 121.76 u, so one mole weighs 121.76 g.
Is antimony a metal?
Antimony is a metalloid: it has properties between metals and nonmetals.
What is the charge of a antimony ion?
Antimony most commonly forms Sb3+ or Sb5+.