Nano-ZnO flakes were synthesized by calcination of the precursor of Zn(OH)2 obtained via the reactive ion exchange method between an ion exchange resin and ZnSO4 solution at room temperature. Scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscope, UV-Vis
diffuse reflection spectrum and Na2EDTA titration were used to characterize the structure features and chemical compositions of the as-prepared ZnO. The results
show that the as-prepared ZnO flakes have uniform structure and high purity. Heat capacities in the temperature range of 83
to 396 K were measured. The measured heat capacities values were compared with those of coarse crystal powders and the difference
between this two heat capacity curves was analyzed.