The standard enthalpies of combustion and formation of crystalline phenylphosphonic, phenylphosphinic, and diphenylphosphinic acids

Abstract The standard enthalpies of formation of crystalline phenylphosphinic (C 6 H 5 PO 2 H 2 ), phenylphosphonic (C 6 H 5 PO 3 H 2 ), and diphenylphosphinic ((C 6 H 5 ) 2 PO 2 H) acids were determined as −(133.3 ± 4.9), −(212.6 ± 2.6), and −(124.2 ± 5.8) kcal th mol −1 at 298.15 K respectively by a combustion-calorimetric method. The difference between the first two enthalpies of formation, (79.3 ± 5.5) kcal th mol −1 , was confirmed independently as (79.0 ± 0.5) kcal th mol −1 by a solution-calorimetric technique.