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| Identifiers | |
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3D model (JSmol) | |
| ChemSpider | |
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| Properties | |
| Na3PS2O2 | |
| Molar mass | 196.072 g mol−1 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Sodium dithiophosphate is thesalt with the formula Na3PS2O2. It is usually supplied as the hydrated solid or as an aqueous solution together with otherthiophosphates such assodium monothiophosphate andsodium trithiophosphate. Both Na3PS2O2 and its hydrate are colorless solids, but commercial samples can appear dark owing to the presence of impurities. It is used to facilitate the isolation of molybdenum from its ores.
The compound has been prepared in a multistep process starting with thebase hydrolysis ofphosphorus pentasulfide:[1]
The salt is isolated as the hydrate Na3PO2S2.(H2O)11. It is prone to hydrolysis, especially when it is heated as an aqueous solutions:
The structure of the anhydrous compound has been examined byX-ray crystallography. The material consists of tetrahedral PO2S23- centers interconnected by Na+ ions. It is assumed that the hydrate retains the tetrahedral PO2S23- centers, but that the Na+ ions are bonded to water.[2][3]
The hydrated salt is used as aflotation agent in the purification ofmolybdenite (MoS2) from other components of the ores. It is a major component of "Nokes reagent" (after Charles M. Nokes, who patented it in 1948[4]). The salt is generated by the reaction ofphosphorus pentasulfide withsodium hydroxide, often using impure reagents to obtain a mixture of the desired salt and related thiophosphates and oxidized species. Molybdenite particles, which are normallyhydrophobic, become hydrophilic in the presence of this salt.[5][6]
Organic esters of dithiophosphate are sometimes also called dithiophosphates.Diethyl dithiophosphoric acid is the parent of one series of these organic compounds. These compounds are salts with the formulaM+(RO)2PS−2 (R =alkyl, usually). These lipophilic salts have also been used as aflotation "collectors" in the purification of various sulfide minerals.[7][8]Zinc dithiophosphates also refers to this class of organic compounds.
