Antimony Pentoxide (molecular formula: Sb2O5) is yellowish powder with cubic crystals, a chemical compound of antimony and oxygen. It always occurs in hydrated form, Sb2O5·nH2O. Antimony(V) Oxide or Antimony Pentoxide is a highly insoluble thermally stable Antimony source. It is used as a Flame retardant in clothing and suitable for glass, optic and ceramic applications.