Résumé:
We report the results of an ab initio study of the structural and thermodynamic properties of the Ca2OsH6
compounds using the pseudopotential plane-wave method within the framework of the density functional theory
with the GGA-PBEsol. The calculated equilibrium structural parameters are in good agreement with the
available experimental data ones when the latter are available. We have investigated the thermodynamic
properties of the Ca2OsH6 system in the temperature range from 0 to 1000 K and the pressure range from 0 to 12
GPa using the quasi-harmonic Debye model as implemented in the Gibbs program. We have successfully
obtained the temperature and pressure dependence of the lattice constant, bulk modulus, thermal expansion, the
constant volume heat capacity and constant pressure heat capacity as these are essential for crystal growth
