Low-temperature polarized single-crystal Raman spectra of the β-alums CSM(SO4)2. 12H2O (M = Mo or Ru) between 275 and 1200 cm−1
✍ Scribed by Robert S. Armstrong; James K. Beattie; Stephen P. Best; Bradley D. Cole; Philip L. W. Tregenna-Piggott
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 693 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0377-0486
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✦ Synopsis
Abstract
Low‐temperature, polarized, single‐crystal Raman spectra of the β‐alums CsM(SO~4~)~2~. 12H~2~O (M = Mo or Ru) and their deuterated analogues were recorded between 275 and 1200 cm^−1^. The internal modes of sulphate and [M(OH~2~)~6~]^3+^ and the external modes of water coordinated to the mono‐ and tervalent cation were assigned. This allowed a comparison between the wavenumbers of the internal modes of second‐ and first‐row transition metal hexaaquacations. The relationship between v~1~(MO~6~) and the M^III^—O bond length is similar for the first‐row transition and Group 13 metals, but is significantly different for the second‐row transition metals. This suggests a non‐ionic contribution to the metal‐water bonding in the latter case. The relative intensities of the v~1~(MO~6~) modes are highly dependent on the identity of the metal; however, the trend in this property is not simply related to either the bond strength, the polarizing power of the cation or the covalent interaction.