Authors: I E Paukov Yulia A Kovalevskaya Irina A Kiseleva Tatiana N Shuriga
Publish Date: 2009/08/28
Volume: 99, Issue: 2, Pages: 709-712
Abstract
Lowtemperature heat capacity of natural zinnwaldite was measured at temperatures from 6 to 303 K in a vacuum adiabatic calorimeter An anomalous behavior of heat capacity function C pT has been revealed at very low temperatures where this function does not tend to zero Thermodynamic functions of zinnwaldite have been calculated from the experimental data At 29815 K heat capacity C pT = 3398 J K−1mol−1 calorimetric entropy S oТ – S o608 = 3291 J K−1 mol−1 and enthalpy Н oТ − Н o608 = 54000 J mol−1 Heat capacity and thermodynamic functions at 29815 K for zinnwaldite having theoretical composition were estimated using additive method of calculationThis work was supported by Russian Fund of Fundamental Investigations of Russian Academy of Sciences Grant No 060564305 and the Integration Interdisciplinary Project No 81 of the Siberian Division Russian Academy of Sciences The authors thank S Purusova analyst of the chemical laboratory of NM Fedorovsky Russian Institute of Mineral Materials for the chemical analysis of the studied sample of zinnwaldite
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