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High temperature mass spectrometric investigation of the equilibrium vapor composition over three-component mixtures of CsI, NaI, and DyI/sub 3/

Journal Article · · High Temp. Sci.; (United States)
OSTI ID:6056915
The molar composition of the saturated vapor phase over ternary iodides of CsI, NaI, and DyI/sub 3/ at 860 to 1060 K was investigated by means of a mass spectrometer equipped with a Knudsen cell evaporator system. Fragmentation patterns and appearance potentials for the most intense ions were determined. Besides the previously detected fragments in the equilibrium vapor above the two-component systems, fragment ions from the complex molecules NaCsDyI/sub 5/, Na/sub 2/CsDyI/sub 6/, NaCs/sub 2/DyI/sub 6/, and Na/sub 3/Cs/sub 2/DyI/sub 8/ were found. Ion current vs temperature data yielded heats of sublimation: ..delta..H/sub s/ (NaCsDyI/sub 5/)/sub 960K/ = 320 +/- 13 kJ/mol; ..delta..H/sub s/ (Na/sub 2/CsDyI/sub 6/)/sub 960K/ = 325 +/- 11 kJ/mol; ..delta..H/sub s/ (NaCs/sub 2/DyI/sub 6/)/sub 960K/ = 348 +/- 15 kJ/mol; and ..delta..H/sub s/ (Na/sub 3/Cs/sub 2/DyI/sub 8/)/sub 960K/ = 366 +/- 17 kJ/mol. From the various high-temperature equilibrium reactions, one may calculate the following heats of formation: ..delta..H/sub f/ (NaCsDyI/sub 5/)/sub g/ = -863 +/- 23 kJ/mol; ..delta..H/sub f/ (Na/sub 2/CsDyI/sub 6/)/sub g/ = -1170 +/- 31 kJ/mol; ..delta..H/sub f/ (NaCs/sub 2/DyI/sub 6/)/sub g/ = -1235 +/- 33 kJ/mol; and ..delta..H/sub f/ (Na/sub 3/Cs/sub 2/DyI/sub 8/) = -1806 +/- 17 kJ/mol.
Research Organization:
Eotvos Lorand Univ., Budapest, Hungary
OSTI ID:
6056915
Journal Information:
High Temp. Sci.; (United States), Journal Name: High Temp. Sci.; (United States) Vol. 18:2; ISSN HITSA
Country of Publication:
United States
Language:
English