Antimony (Sb)
Metalloid · p-block · period 5 · group 15
Hard, brittle, silvery-white, flaky metalloid.
Antimony (symbol Sb) is chemical element number 51, a metalloid in group 15, period 5 of the periodic table. Its standard atomic weight is 121.76 and its electron configuration is [Kr] 4d10 5s2 5p3. At room temperature it is a solid. Its symbol Sb is from 'stibium', the ancient black eye cosmetic (kohl).
Properties
| Atomic number | 51 |
|---|---|
| Atomic mass | 121.76 |
| Category | Metalloid |
| Block | p-block |
| Group · Period | 15 · 5 |
| Electron configuration | [Kr] 4d10 5s2 5p3 |
| Electrons per shell | 2, 8, 18, 18, 5 |
| State at 25 °C | solid |
| Melting point | 903.78 K |
| Boiling point | 1860 K |
| Density | 6.697 g/cm³ |
| Electronegativity (Pauling) | 2.05 |
| Radioactive | No |
| Origin | primordial |
| Discovered | Known since antiquity · Known since antiquity |
Key facts about Antimony
- Its symbol Sb is from 'stibium', the ancient black eye cosmetic (kohl).
- One of the few substances that expands when it solidifies, giving sharp castings.
- The main flame retardant in plastics, textiles and electronics.
- Hardens soft lead for batteries, bullets and type metal.
What Antimony is used for
Flame retardants, lead-acid battery plates, alloys, semiconductors, glass and ceramics.
Where it sits in the periodic table
Antimony is in group 15, period 5, of the p-block. Its electron configuration [Kr] 4d10 5s2 5p3 means its outermost shell holds 5 electrons, which is what places it here and explains much of its chemistry. See Antimony on the interactive table →
Antimony — frequently asked questions
What is Antimony used for?
Flame retardants, lead-acid battery plates, alloys, semiconductors, glass and ceramics.
Is Antimony radioactive?
No. Antimony has at least one stable isotope and is not radioactive.
What is the electron configuration of Antimony?
Antimony has the electron configuration [Kr] 4d10 5s2 5p3, which is 2, 8, 18, 18, 5 electrons per shell.
What group and period is Antimony in?
Antimony is in group 15, period 5, in the p-block. Its outer shell holds 5 electrons.
Who discovered Antimony?
Antimony has been known since ancient times.