Conferences

Heat Capacity of Yb4Hf3O12 at 57–302 K.

    

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2016, #07/08
http://www.materials.kiev.ua/article/2224

Abstract

The heat capacity of Yb4Hf3O12 is studied for the first time in the range 57–302 K by adiabatic calorimetry. It is shown that Ср of ytterbium hafnate changes monotonically and no anomalies are observed. Temperature dependencies of the principal thermodynamic functions in the range 10–300 K are obtained. The heat capacity, entropy, reduced Gibbs energy, and enthalpy are determined for standard conditions: C°p(298,15K) = 408,4  ± 1,6 J • mol–1 • К–1; S°(298,15K)  = 410,5  ± 3,3 J • mol–1 • К–1;  Ф’ (298,15K) = 187,2 ± 2,8 J • mol–1 • К–1; H°(298,15K) - H° (0K) = 66566 ± 333 J • mol–1. The difference between the experimental heat capacities and those evaluated by the Neumann–Kopp rule of additivity (as a weighed sum of heat capacities of oxides) in the range 70–300 K is no more than 4.65%, while the difference in C°p(298,15K)is 0.7%.


ENTHALPY, ENTROPY, HEAT CAPACITY, REDUCED GIBBS ENERGY, THERMODYNAMICS, YTTERBIUM HAFNATE YB4HF3O12