Atomic Properties of Sb
- Atomic Number of Sb
- 51
- Atomic Mass of Sb
- 121.7600 u
- Electron Configuration
- [Kr] 4d10 5s2 5p3
- Electronegativity
- 2.05
- Block
- p-block
- Group
- 15
- Period
- 5
Antimony's symbol, Sb, preserves the Latin name stibium and a history older than the modern element. Powdered stibnite, antimony sulfide, was used in ancient eye cosmetics called kohl. Historical use does not establish safety: antimony compounds vary in toxicity, and modern cosmetics and medicines require evidence and regulation beyond tradition.
The element is a brittle, silvery metalloid, usually obtained from stibnite. Small additions can harden lead and improve alloys used in batteries, bearings, and other cast products. Antimony compounds also appear in semiconductor devices, glass, ceramics, and pigments. The specific compound and material design determine the function.
Antimony trioxide has an especially misunderstood role in flame-retardant materials. It is commonly a synergist, working with halogenated flame retardants to interfere with flame chemistry. It is not a universal coating that makes a material unable to burn. Fire performance depends on formulation, geometry, exposure, smoke, and testing, while health and environmental concerns influence which systems remain acceptable.
Two stable isotopes, antimony-121 and antimony-123, make up natural antimony. Radioactive antimony isotopes serve as tracers and arise in fission. Chemically, antimony commonly uses +3 and +5 oxidation states, helping it bridge metallic and nonmetallic behavior.
Antimony is a Contrarian whose old stories need precise translation. Kohl was a mineral preparation, Sb is a linguistic fossil, alloy hardening needs only a small addition, and flame retardancy is cooperative chemistry rather than magic. The element's real character appears when the historical object is unpacked into compound, structure, and mechanism.