Calorimetric study of dihydrogen phosphates of certain elements

Abstract

The std. heals of formation of Mn(H2PO4)2.2H2O [10234-99-8], Zn(H2PO4)2.2H2O [13986-21-5], and Cd(H2PO4)2.2H2O [13477-16-2] are -815.2 ± 0.6, -787.5 ± 0.5, and -772.9 ± 0.6 kcal/mol, resp. These values were calcd. from the heats of soln. of these compds. in aq. HCl at 25° (5.71 ± 0.17, 6.70 ± 0.11, and 4.51 ± 0.10 kcal/mol, resp.) and the heats of soln. of ZnO and CdO, (-15.97 ± 0.14 and -25.41 ± 0.28 kcal/mol, resp.).