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Formation and decomposition of Lanthanum Monoxocarbonate
Author(s) -
Yamaguchi Osamu,
Sugiura Koji,
Shimizu Kiyoshi
Publication year - 1984
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.19845140725
Subject(s) - lanthanum , thermal decomposition , activation energy , decomposition , amorphous solid , crystallization , chemistry , hydrolysis , inorganic chemistry , infrared spectroscopy , kinetics , chemical decomposition , nuclear chemistry , materials science , crystallography , organic chemistry , physics , quantum mechanics
Amorphous lanthanum carbonate was prepared by hydrolysis of lanthanum isopropoxide using ammonia water in the atmosphere. Lanthanum monoxocarbonate, La 2 O(CO 3 ) 2 · H 2 O, crystallizes when this amorphous material was washed with hot water. The crystallization and thermal behavior of the crystalline material are studied by X‐ray diffraction, thermal analysis, and infrared spectroscopy. The decomposition of La 2 O(CO 3 ) 2 · H 2 O into type‐IA (LaO) 2 CO 3 is observed at 440 to 540°C. Decomposition isotherms are described by the contracting cube equation, the activation energy being 42.6 kcal mol −1 . Type‐IA (LaO) 2 CO 3 subsequently decomposes to A‐type La 2 O 3 at 750 to 870°C. The kinetics is also interpreted in terms of the contracting cube equation, the activation energy being 58.3 kcal mol −1 .