The standard molar enthalpy of formation of ZrMo2O8

Abstract The molar enthalpies of a solution of ZrMo 2 O 8 , Mo, and ZrF 4 in 10 mol dm −3 HF(aq)+4.41 mol dm −3 H 2 O 2 (aq) have been measured using an isoperibol-type calorimeter. From these results and other auxiliary data, the standard molar enthalpy of formation of ZrMo 2 O 8 has been calculated to be Δ f H 0 m (298.15 K) = −2588.6±4.5 kJ mol −1 . This value of enthalpy of formation of ZrMo 2 O 8 is consistent with the second law of enthalpy of formation of ZrMo 2 O 8 determined in this laboratory by the transpiration technique.