Molecular structures and thermodynamic properties of 12 gaseous cesium-containing species of nuclear safety interest: Cs2, CsH, CsO, Cs2O, CsX, and Cs2X2 (X = OH, Cl, Br, and I)

Ab initio electronic structure calculations at the coupled cluster level with a correction for the triples extrapolated to the complete basis set limit have been made for the estimation of the thermochemical properties of Cs2, CsH, CsO, Cs2O, CsX, and Cs2X2 (X = OH, Cl, Br, and I). The standard enthalpies of formation and standard molar entropies at 298 K, and the temperature dependence of the heat capacities at constant pressure were evaluated. The calculated thermochemical properties are in good agreement with their literature counterparts. For Cs2, CsH, CsOH, Cs2(OH)2, CsCl, Cs2Cl2, CsBr, CsI, and Cs2I2, the calculated ΔfH298K∘ values are within chemical accuracy of the most recent experimental values. Based on the excellent agreement observed between our calculated ΔfH298K∘ values and their literature counterparts, the standard enthalpies of formation at 298 K are estimated to be the following: ΔfH298K∘ (CsO) = 17.0 kJ mol−1 and ΔfH298K∘ (Cs2Br2) = −575.4 kJ mol−1.

► Electronic structure of cesium-containing species are studied by high level ab initio methods.
► Standard enthalpies of formation at 298 K are estimated and compared to available literature data.
► Standard molar entropies and temperature dependence of the heat capacities at constant pressure were evaluated.