VIBRATIONAL SPECTRA OF THE $BO^{-}_{2}$ ION IN SOLID SOLUTION.
Loading...
Date
1962
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The metaborate ion, $BO^{-}_{2}$, has been incorporated in dilute solid solution in crystals of KCl, KBr, and other alkali halides. The ion is stable and soluble in fused alkali halide, and upon cooling occupies a halide lattice site. Infrared spectra of solid solutions have been studied at $300^{\circ}K$ and at $77^{\circ}K$. and bands observed from species containing $B^{10}, B^{11}$, and $O^{18}$ in normal abundances, and from species containing isotopically enriched $O^{17}$. Half-widths of the bands are approximately one $cm^{-1}$ at $300^{\circ}K$, allowing precise measurement of isotope shifts. Analysis of the spectra shows $BO^{-}_{2}$ to be linear, and comparable to $CO_{2}$. Approximate vibrational frequencies for $B^{11}O^{16-}_{2}$ (values vary somewhat with the host lattice) are $\nu_{3}$ (asymmetric stretch) $1970 cm^{-1}, \nu_{2}$ (bend) $610 cm^{-1}$, and $\nu_{1}$ (symmetric stretch) $1070 cm^{-1}$. No infrared absorption of $\nu_{1}$ and $2\nu_{3}$ can be observed at high concentrations, indicating that the $BO^{-}_{2}$ environment is highly symmetric. The asymmetric stretch, $\nu_{3}$, absorbs strongly in the infrared and may be easily observed at concentrations below a part per million. The absorptions of $BO^{-}_{2}$ are affected by cation impurities, through the formation of ''ion pairs'' in the lattice.
Description
Author Institution: Physics Division, Oak Ridge National Laboratory