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Knudsen measurements of the sublimation and the heat of formation of GeSe 2 [1]
Author(s) -
Irene E. A.,
Wiedemeier H.
Publication year - 1976
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19764240312
Subject(s) - knudsen number , sublimation (psychology) , atmospheric temperature range , standard enthalpy of formation , analytical chemistry (journal) , materials science , enthalpy of sublimation , enthalpy , crystallite , thermodynamics , mass spectrometry , chemistry , organic chemistry , psychology , physics , psychotherapist , chromatography , metallurgy
Knudsen effusion studies of the sublimation of polycrystalline GeSe 2 have been performed employing mass spectrometry in a temperature range of about 610–750 K and vacuum microbalance techniques in the temperature range 614–801 K and at pressures ranging from about 10 −7 − 10 −4 atm. The results demonstrate that GeSe 2 vaporizes congruently under present experimental conditions according to the predominant reaction (1) GeSe 2 (s) = GeSe(g) + 1/2 Se 2 (g) and a minor reaction (2) GeSe 2 (s) = GeSe 2 (g). The mean values for the third law heat and second law entropy of reaction (1) based on direct mass‐loss data are ΔH° 298 = 70.4 ± 2 kcal/mole and ΔS° 298 = 64.7 ± 2 eu. From these the standard heat of formation and absolute entropy of GeSe 2 (s) were calculated to be −21.7 ± 2 kcal/mole and 24.6 ± 2 eu, respectively.