Sodium Thiophosphate Hydrate

Sodium Thiophosphate hydrate (Na₃PO₃S xH₂O), also called trisodium thiophosphate or sodium monothiophosphate, is a crystalline powder which can range in color from white to pale yellow-green.  It is hygroscopic, and soluble in water.

Thiophosphates are a group of compounds with the general formula [PS_4-xO_x]^3- (x = 0, 1, 2, 3), where one or more of the oxygen atoms on the phosphate ion PO₄^3- are substituted with a sulfur atom.  There are also organic thiophosphates such as (RO₂)PS^2- where “R” represents an alkyl or aryl group.  There are also thiophosphates formed by high-temperature solid state reactions with phosphorus- and sulfur-containing precursors creating [P₂S₆]^4- or [PS₄]^3- subunits.  Our product is Na₃PO₃S, the monothiophosphate.

Sodium Thiophosphate is mainly a laboratory reagent. For example, chemists at University of Cambridge discovered it enables thiolysis of cyanohydrins, forming thioamides via a sulfur-based nucleophilic reaction. Researchers at Durham University found it can also reduce azides to primary amines, achieving high yields under reflux conditions.

1. Ritson, D. J., Xu, J., & Sutherland, J. D. (2017). Thiophosphate – A Versatile Prebiotic Reagent? Synlett, 28(01), 64–67. https://doi.org/10.1055/s-0036-1589414
2. Norcliffe, J. L., Conway, L. P., & Hodgson, D. R. W. (2011). Reduction of alkyl and aryl azides with sodium thiophosphate in aqueous solutions. Tetrahedron Letters, 52(21), 2730–2732. https://doi.org/10.1016/j.tetlet.2011.03.083