Abstract: The size of nano ZnO powders was determined to be 30 nm in diameter by SEM. The isobaric molar heat capacity C_p of the nano ZnO was measured with high precision adiabatic low-temperature calorimeter in temperature range from 83 K to 350 K. The relationship of C_p with temperature T was established as: C_p＝－3.249＋0.2400T－3.413×10^－4T ²＋4.485×10^－7T ³. The thermodynamic functions of the nano ZnO, relative to the standard temperature of 298.15 K, were derived based on the heat capacity data through thermodynamic relationship. The measured C_p values were compared with those of coarse crystal and 18 nm ZnO powders cited from literature and the difference between the C_p curves was analyzed.

Key words: Nano ZnO, Low-temperature heat capacity, Thermodynamic functions