... of the Sodium metabisulphite1,Molecular formula : Na2S2O52,Molecular weight : 190.103,Appearance : white or light yellow crystalline powder4,Main content :96.5%min 5,Competitive ... . Kerry Xiao(0086-13762006068) in Yueyang Sanxiang Chemical Co.,Ltd. 96.5% min Sodium metabisulfite (SM158)