Mass Spectrometric Study of Stability, Thermochemistry and Structures of the Gaseous Oxyacid Salts
Experimental data obtained by Knudsen Effusion Mass Spectrometry and results of quantum-chemical calculations on the structure and thermodynamic properties of gaseous oxyacid salts were systematized. A criterion of thermal stability of these compounds was offered and regularities in the atomization enthalpies were established.
Thermodynamic study of some chromium-containing gaseous molecules by high-temperature mass spectrometry.
A number of gaseous oxyacid salts have been identified by Knudsen effusion mass spectrometry, while vaporizing Cr(2)O(3) and mixtures of Cr(2)O(3)+Nb(2)O(5), Cr(2)O(3)+Ta(2)O(5), Cr(2)O(3)+BaO, and Cr(2)O(3)+Mg(2)P(2)O(7) from molybdenum and tungsten cells. The stabilities of the gaseous molecules CrMoO(3), CrMoO(4), CrMoO(5), CrWO(3), CrWO(4), CrWO(5), CrNbO(3), CrTaO(3), CrPO(2), CrPO(3), BaCrO(2) and BaCrO(3) were deduced from the measurements. The thermodynamic properties of this gaseous chromium-containing species are summarized. Prediction is tentatively made of the stability of as-yet unstudied gaseous molecules.
Double‐Oven Experiments with Lithium Halide Vapors
A double‐oven apparatus described here has been operated within a mass spectrometer. By independently controlling the pressure and temperature of the vapor in the oven, the fragmentation patterns and relative ionization cross sections of the components of a complex vapor phase may be distinguished. Superheating the vapor and thereby producing species of lower molecular weight simplifies the mass spectrum and minimizes confusion due to fragmentation effects. This technique has been applied to the lithium halide vapors. Fragmentation patterns, ionization cross sections of dimers relative to those of the monomers, and energies of dimerization are reported.