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Vaporization and thermodynamics of the Cs 2 O–MoO 3 system studied using high‐temperature mass spectrometry
Author(s) -
Stolyarova Valentina L.,
Vorozhtcov Viktor A.,
Lopatin Sergey I.,
Shugurov Sergey M.,
Simonenko Elizaveta P.,
Simonenko Nikolai P.,
Masaki Kurata,
Costa Davide
Publication year - 2021
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.9097
Subject(s) - chemistry , vaporization , molybdenum , mass spectrometry , analytical chemistry (journal) , atmospheric temperature range , inorganic chemistry , thermodynamics , organic chemistry , physics , chromatography
Rationale Cesium and molybdenum are fission products of uranium dioxide fuel in nuclear reactors, which interact with each other depending on the oxygen potential of the fuel. This leads to formation of various compounds of the Cs 2 O–MoO 3 system, which are exposed to high temperatures during operation of a reactor or a severe accident at a nuclear power plant. This is why the study of the vaporization and thermodynamics of compounds in the Cs 2 O–MoO 3 system is important. Methods Synthesis of the compounds in the Cs 2 O–MoO 3 system was carried out by sintering Cs 2 MoO 4 and MoO 3 . Characterization of the samples was accomplished with the use of XRD, TGA/DSC/DTA, IR spectroscopy, and ICP emission spectroscopy. Vaporization of the samples under study was carried out from a platinum effusion cell using an MS‐1301 mass spectrometer developed for high‐temperature studies of low‐volatility substances. Results The temperature dependences of partial pressures of vapor species were determined over pure MoO 3 and Cs 2 MoO 4 in the ranges 870–1000 K and 1030–1198 K, respectively. MoO 3 , Mo 2 O 6 , Mo 3 O 9 , Mo 4 O 12 , and Mo 5 O 15 were shown to be the main vapor species over the Cs 2 O–MoO 3 system in the temperature range 850–1020 K. The component activities, Gibbs energies of mixing, and excess Gibbs energies were obtained as functions of the component concentration at 900, 950, and 1000 K. Conclusions The thermodynamic properties of the Cs 2 O–MoO 3 system found in the study evidenced negative deviations from ideality. The MoO 3 and Cs 2 MoO 4 partial molar enthalpies of mixing, the Cs 2 MoO 4 partial vaporization enthalpy, and the total enthalpy of mixing in the Cs 2 O–MoO 3 system at 1000 K were obtained for the first time.