The low temperature heat capacity of the ZnO-CoO solid solution system was measured from 2 to 300 K using the heat capacity option of a Quantum Design Physical Property Measurement System (PPMS). The thermodynamic functions in this temperature range were derived by curve fitting. The standard entropies of bulk ZnO and bulk ZnO-CoO (wurtzite, 18 mol% CoO) at T = 298.15 K were calculated to be (43.1 +/- 0.4) J . mol (1) . K (1) and (45.2 +/- 0.5) J . mol (1) . K (1), respectively. The surface entropy of ZnO was evaluated to be (0.02 +/- 0.01) mJ . K (1) . m (2), which is essentially zero. No sharp magnetic transitions were observed in the solid solution samples. The nanophase solid solution, 12 mol% CoO, appears to bind H2O on its surface more strongly than ZnO. (C) 2013 Elsevier Ltd. All rights reserved.