Tin is a chemical element with the symbol Sn (Latin: stannum) an atomic number 50. This silvery, malleable poor metal that is not easily oxidized in air and resists corrosion, is found in many alloys and is used to coat other metals to prevent corrosion. Tin is obtained chiefly from the mineral cassiterite, where it occurs as an oxide. It can be alloyed with copper to make bronze. Pewter alloys contain from 85% up to 99% tin.