Standard heats of formation of the sodium triphosphates Na5P3O10(cI), Na5P3O10(cII) and Na5P3O10˙ 6H2O(c)

Abstract

The standard heats of formation of Na₅P₃O₁₀(c) phases I and II and Na₅P₃O₁₀˙ 6H₂O(c) have been determined by solution calorimetry. The values obtained are : ΔH^°_{f 298}Na₅P₃O₁₀(cI)=– 1056.5±1.5 kcal mole^–1, ΔH^°_{f 298}Na₅P₃O₁₀(cII)=–1059.1±1.5 kcal mole^–1, ΔH^°_{f 298}Na₅P₃O₁₀˙ 6H₂O(c)=–1485.7±1.6 kcalzmole^–1.