Zinc oxide represents an important material with a wide variety of applications. At the temperature T=298.15 K and standard pressure p(o) = 100 kPa ZnO exists in the hexagonal wurtzite structure, which undergoes a transformation to rock salt polymorph under the pressure of approximate to 9 GPa. A consistent set of thermodynamic functions for ZnO in the high-pressure rock salt modification has been established on the basis of thorough evaluation of experimental and calculated data. Using literature data for wurtzite ZnO, standard enthalpy of formation at 298.15 K for rock salt ZnO have been assessed as Delta H-f(o)(298.15 K)= -326.69 kJ mol(-1). Standard entropy S-m(o)(298.15 K)=45.42 J K-1 mol(-1) was derived from published low temperature heat capacity. The temperature dependence of the standard molar heat capacity above room temperature in the form C-pm(o) = 45.91 + 0.009089T - 604976/T-2 + 4.159 x 10(-6)T(2) (J K-1 mol(-1)) has been derived. The dataset is consistent with the transition pressure p(tr) =9.6 GPa for wurtzite to rock salt transformation at room temperature. (C) 2013 Elsevier B.V. All rights reserved.