Abstract
The coordination structures of the Cu ions in the mixed solvent system of HCONH2-HCOONH4 at room temperature and 100 °C have been investigated using the EXAFS (extended X-ray absorption fine structure) method for the Cu K-edge, together with visible absorption spectrum analyses and ion-exchange experiments. The Cu ions, which are divalent, CuII, at room temperature, are reduced to univalence, CuI, by heating with HCOO- ions, ca. 80% of CuII ions are transformed into CuI, ions at 100 °C. In the mixed solvent system, it was found that CuII ions form neutral [Cu(HCOO)2(HCONH2)4] octahedra, distorted by the Jahn-Teller effect, with four short Cu-O bond lengths of ca. 1.97 Å and two long Cu-O bond lengths of ca. 2.82 Å at room temperature, and CuI ions form cationic [Cu(HCONH2)3]+ plane triangles with three Cu-O bond lengths of ca. 1.90 Å at 100 °C. The transition of the coordination structures occurs reversibly in the mixed solvent system as a function of the temperature.
Original language | English |
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Pages (from-to) | 1721-1727 |
Number of pages | 7 |
Journal | Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics |
Volume | 85 |
Issue number | 11 |
DOIs | |
Publication status | Published - Dec 1 1989 |
Externally published | Yes |
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry