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Updated: Aug 20, 2025

Development and Validation of Chromium Getters for Solid Oxide Fuel Cell Power Systems
Published on: May 26, 2019
Speciation of chromium aqua and chloro complexes in hydrochloric acid solutions at 298 K
Masahito Uchikoshi1, Daisuke Akiyama1, Ken'ichi Kimijima2
1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University Katahira 2-1-1, Aoba Sendai 980-8577 Japan masahito.uchikoshi.b5@tohoku.ac.jp +81 22 217 5859.
Abstract:
The distribution of metal aqua and chloro complexes is fundamental information for analysis of a chemical reaction involving these complexes. The present study investigated the speciation and structures of chromium aqua and chloro complexes using the thermodynamic model fitting analysis of UV-vis/X-ray absorption spectra. The existence of a negatively charged species was examined by adsorbability of chromium species on a strong base anion exchanger. In the results, a planar square [CrIII(H2O)4]3+, a planar square or distorted tetrahedral [CrIIICl(H2O)3]2+, a trigonal bipyramidal [CrIIICl3(H2O)2]0, and a distorted octahedral [CrIIICl4(H2O)2]- were confirmed and the thermodynamic parameters of complexation reactions were quantitatively determined. Investigation of the evolution of speciation of chromium aqua and chloro complexes in a pH 1 solution suggested the existence of [CrIIICl2(H2O) ]+ (m = 2 or 3) during the hydration process, which diminished in the equilibrium state. The kinetic analysis deserves further investigation to understand the speciation process quantitatively.
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