Thermal expansion and functions of mixing of clinopyroxenes CaMgSi2O6-CaAl2SiO6

Thermal expansion of three clinopyroxenes of the series CaMgSi2O6-CaAl2SiO6 was studied by X-ray spectroscopy. The end-members of the series, (Di) and (CaTs), were studied in the temperature range 100-300 K, and the intermedi ate member (Di(50)CaTs(50)) - in the range 100-660 K. Using the advanced te chnique based an the Debye-Mie-Gruneisen theory, we performed inter- and ex trapolations of experimental data to 1500 K and estimated the coefficients of thermal expansion (alpha(V) (298) (K) X 10(-6) K-1) for Di, Di(50)CaTs(5 0), and CaTs - 23.5, 22.7, and 16.9, respectivley. Also, the excessive func tions of mixing (Delta V-mix(0), Delta H-mix(0), Delta S-mix(0) and Delta G (mix)(0)) of these clinopyroxenes were estimated. The temperature dependenc e of these functions is considered.