Antimony (Sb)
Element 51 · Metalloid · Solid at 25 °C · Group 15, Period 5
Antimony hardens lead for batteries and ammunition, and antimony compounds are widely used flame retardants.
On the periodic table, antimony sits in group 15 — the pnictogens (nitrogen group) — in period 5. It is one of 6 elements classified as a metalloid, and at room temperature (25 °C) it is a solid.
Metalloids line the zig-zag “staircase” between the metals and nonmetals and behave a bit like both: they look metallic but are brittle and conduct electricity only moderately well. That in-between conductivity — a semiconductor's — is exactly what modern electronics is built on.
Properties of antimony
| Atomic number (Z) | 51 |
|---|---|
| Symbol | Sb |
| Atomic mass | 121.76 |
| Category | Metalloid |
| Group | 15 |
| Period | 5 |
| Block | p-block |
| Metal / nonmetal | Metalloid |
| State at 25 °C | Solid |
| Electron configuration | [Kr] 4d10 5s2 5p3 |
| Electronegativity (Pauling) | 2.05 |
| Melting point | 630.63 °C (903.78 K / 1,167.13 °F) |
| Boiling point | 1,587 °C (1,860.15 K / 2,888.6 °F) |
| Density | 6.685 g/cm³ |
Position in the periodic table
Antimony shares group 15 — the pnictogens (nitrogen group) with Nitrogen (N), Phosphorus (P), Arsenic (As), Bismuth (Bi), Moscovium (Mc). Elements in the same group have the same number of outer electrons, so they tend to behave alike chemically — comparing them is one of the fastest ways to see periodic trends in action.
Physical properties
Antimony melts at 630.63 °C (903.78 K / 1,167.13 °F) and boils at 1,587 °C (1,860.15 K / 2,888.6 °F), giving it a liquid range of about 956.4 °C at standard pressure.
Its density is 6.685 g/cm³.
See also: the interactive periodic table, how to read the periodic table, metals, nonmetals & metalloids.