Thermodynamic and thermophysics properties of synthetic britholite SrPr4(SiO4)3O

• Published in: The Journal of chemical thermodynamics 2017-05, Vol.108, p.38-44
• Main Authors: Knyazev, A.V., Bulanov, E.N., Smirnova, N.N., Korokin, V.Zh, Shushunov, A.N., Blokhina, A.G., Ziyan, Xu
• Format: Article
• Language: English
• Subjects: Apatite; Britholite; Heat capacity; Synthesis; Thermal expansion; Thermodynamic functions
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2017.01.002

[Display omitted] •Temperature dependence of heat capacity of SrPr4(SiO4)3O has been measured by precision adiabatic vacuum calorimetry.•The thermodynamic functions of the SrPr4(SiO4)3O have been determined for the range from T→0 to 347K.•The character of heterodynamics of structure was detected.•The phase transition at 9.2K was determined.•Thermal expansion coefficients of the SrPr4(SiO4)3O crystal structure were calculated. In the present work the temperature dependences of strontium-praseodymium oxysilicate heat capacity have been measured for the first time in the range from 4.7 to 347K by precision adiabatic vacuum calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity Cp°(T), enthalpy H°(T)−H°(0), entropy S°(T)−S°(0) and Gibbs function G°(T)−H°(0), for the range from T→0 to 347K. Thermal expansion coefficients of the SrPr4(SiO4)3O crystal structure were calculated using in situ thermoroentgenography (αa=10.0·10−6K−1; αc=6.7·10−6K−1;αV=26.9·10−6K−1). On the basis of features of thermal expansion ion conductivity mechanism in apatites was explained.