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Heat Capacities and Thermodynamic Properties of Lanthanum/Holmium Perchlorate Complexes with Glycine
Author(s) -
BeiPing Liu,
ZhiCheng Tan,
HuaGuang Yu,
LiXian Sun,
XiaoZheng Lan,
YouYing Di,
ZhenGan Chen,
Ping Liu
Publication year - 2003
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20030210409
Subject(s) - chemistry , calorimetry , enthalpy , thermogravimetry , atmospheric temperature range , holmium , phase transition , heat capacity , adiabatic process , standard enthalpy of formation , lanthanum , thermodynamics , analytical chemistry (journal) , inorganic chemistry , organic chemistry , laser , physics , optics
The heat capacities of the two complexes, [La 2 (Gly) 6 (H 2 O) 4 ]‐(ClO 4 ) 6 and [Ho 2 (Gly) 4 (H 2 O) 4 ](ClO 4 ) 6 ·2H 2 O (Gly = glycine), were measured by adiabatic calorimetry in the temperature range from 78 to 375 K. A solid‐solid phase transition was found between 322.87 and 342.29 K for [Ho 2 (Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·2H 2 O, and the peak temperature, the enthalpy and the entropy of the transition were obtained to be 330.94 K, 11.65 kJ·mol −1 and 35.20 J· K −1 ·mol −1 , respectively. No indication of any phase transition or thermal anomaly was observed for [La 2 (Gly) 6 (H 2 O) 4 ] (ClO 4 ) 6 . Thermal stabilities of the two complexes were investigated by thermogravimetry in the temperature range of 40–800°C. The possible mechanisms for the thermal decompositions were proposed according to the TG and DTG curves.