Antimony

Antimony is a chemical element with the symbol Sb. or the atomic number 51. This is lustrous gray metalloid, If was been found in the nature.
Antimony discovered in year 815 AD.
Antimony have two stable istopes: 121Sb the natural abundance is 57.36% which is common isotope. and the 123Sb, which are 42.64% natural abundance of isotope little common of this time.
Antimony have 29 nuclear isomers has been characterized.
The abundance of antimony in the Earth's crust which estimates 0.2 parts per million. This element are rare only this time.