Title: Sodium Phosphate, Tribasic
CAS Registry Number: 7601-54-9
Synonyms: Trisodium orthophosphate; trisodium phosphate; TSP
Trademarks: Oakite
Molecular Formula: Na3O4P
Molecular Weight: 163.94
Percent Composition: Na 42.07%, O 39.04%, P 18.89%
Line Formula: Na3PO4
Literature References: Crystallizes with 8 and 12 mols of H2O.
Derivative Type: Dodecahydrate
Properties: Colorless or white crystals. When rapidly heated melts at ~75°. Does not lose the last mol of water even on moderate ignition. d 1.6. Sol in 3.5 parts water, 1 part boiling water; insol in alcohol. The aq soln is strongly alkaline. pH of 0.1% soln: 11.5; of 0.5% soln: 11.7; of 1.0% soln: 11.9. Technical crystals are sometimes made with excess alkali to prevent caking and give more alkaline solutions. LD50 orally in rats: 7.40 g/kg, H. F. Smyth
et al., Am. Ind. Hyg. Assoc. J. 30, 470 (1969).
Melting point: When rapidly heated melts at ~75°
Density: d 1.6
Toxicity data: LD50 orally in rats: 7.40 g/kg, H. F. Smyth
et al., Am. Ind. Hyg. Assoc. J. 30, 470 (1969)
Use: In photographic developers; clarifying sugar; removing boiler scale, softening water; manuf paper; laundering; tanning leather; in detergent mixture.
