Irreversible spectral changes of cobalt(II) by moderate heating in sol-gel glasses, and their ligand field rationalization
✍ Scribed by R. Reisfeld; V. Chernyak; M. Eyal; C.K. Jørgensen
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- English
- Weight
- 585 KB
- Volume
- 164
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Cobalt( II) nitrate or acetate added to a precursor methanolic solution of TMOS (slllcon tetrakis-methoxide ), which hydrolyzes and polycondensates when heated above 3OO"C, forms blue fdms showing three strong bands at 15600, 16800 and 19000 cm-' (like a known complex with two acetone and two chloro ligands). The absorption spectra even of tetrahalides and crystalline oxides (e.g. spinel-type) do not agree closely with regular tetrahedral coordination, and angular overlap estimates suggest DZh holohedrized symmetry in the glass. Inner shell 3p mixing with 3d may provide intensities not feasible in octahedral complexes.