Also Called: Sulphur trioxide;Sulfur trioxide;Schwefeltrioxid;SULFUR TRIOXIDE (ALSO CALLED SULFURIC ANHYDRIDE);SULFURIC ANHYDRIDE (ALSO CALLED SULFUR TRIOXIDE);Sulfur trioxide [stabilized];oxid sírový;SULFURIC ANHYDRIDE;ซัลเฟอร์ไตรออกไซด์;SULFUR TRIODKSIDA;三氧化硫;三酸化硫黄