monoclinic crystal,used in fixers, plating, leather, reductant, dechlorinating agent. 1, Chemical name: Sodium thiosulfate 2, Structural formula:3, Molecular formula: Na2S2O2·5H2O4 ... : used in fixers, plating, leather, reductant, dechlorinating agent, sulfur dyeing agent, as a blush preventive agent, and as a disinfectant. and decolor agent Sodium Thiosulfate