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Thermal Dissociation of CdO and CdFe 2 O 4
Author(s) -
Knacke Ottmar,
Zimmermann Edwin
Publication year - 1993
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.19936191027
Subject(s) - endothermic process , cadmium oxide , stoichiometry , enthalpy , analytical chemistry (journal) , gibbs free energy , chemistry , ionic bonding , cadmium , oxide , ion , materials science , thermodynamics , adsorption , physics , organic chemistry , chromatography
Knudsen effusion mass spectrometry has been applied to two identical alumina cells inside a revolving molybdenum cylinder. The one cell was filled with cadmium ferrite and the other with cadmium oxide, and the ionic current intensities of Cd + and O 2 + were measured above both samples. The ratio between the intensities above the ferrite and above the oxide was found to be approx. 0.6, for both Cd + and O 2 + . From this ratio and from calorimetric data the Gibbs energy of the reaction CdO + Fe 2 O 3 → CdFe 2 O 4 could be derived. The endothermic ferrite is stable above 677 K. Its normal enthalpy, H° 298 is ‐ 1 065 kJ/mol, and its normal entropy, S° 298 is 168 J/K mol. The non‐stoichiometry of CdO is discussed.