ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Phase Chemistry and Thermochemistry of Coordination of Chromium Chloride to Histidine

S. Chen, S. Gao, M. Ji, R. Hu, and Q. Shi

Department of Chemistry, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Northwest University, Xi’an, 710069, P. R. China

E-mail: weizhang@nwu.edu.cn

Received: 6 September 2001

Abstract: The solubility properties of the ternary systems CrCl₃—His—H₂O at 298.15 K in the entire concentration range have been investigated by the phase equilibrium method and the corresponding solubility diagrams (phase diagrams) have been constructed. The congruently soluble complexes Cr(His)Cl₃ ·H₂O, Cr(His)₂Cl₃ ·H₂O, and Cr(His)₃Cl₃ ·H₂O have been prepared. The compositions of these complexes were determined by chemical and elemental analyses. The enthalpies of reaction of chromium chloride with histidine in water have been measured by microcalorimeter. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy, and the activation Gibbs energy), the rate constant, three kinetic parameters (the activation energy, the pre-exponential constant, and the reaction order) are obtained.

Full paper in Portable Document Format: 563a162.pdf

Chemical Papers 56 (3) 162–167 (2002)