Heat of hydrolysis of phosphorus pentachloride, and heat of formation of aqueous orthophosphoric acid

Abstract

Measurements of the heat of hydrolysis of crystalline phosphorus pentachloride at 25 °C are reported. In conjunction with the available standard heat of formation of PCl₅, cryst., (ΔH _f=–106.0 kcal/mole), the hydrolysis measurements lead to ΔH _f[H₃PO₄, (in 100 H₂O)]=–309.80 ± 0.35 kcal/mole.