Antimony

Antimony is a chemical element with symbol Sb (from Latin: stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times and were used for cosmetics; metallic antimony was also known, but it was erroneously identified as lead. It was established to be an element around the 17th century.
Symbol: Sb
Electron configuration: Kr 4d10 5s2 5p3
Atomic number: 51
Melting point: 630.8 °C
Discoverer: Jābir ibn Hayyān
Atomic mass: 121.76 ± 0.001 u