Knowledge Bank

“The infrared spectra of the $BF4\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$ ion have been measured in dilute solid solutions in various alkali halide pellets. Using small grating spectrometers, careful measurements have been made of the dependence of the vibrational frequencies on the nature of the host lattice and on the temperature. Tetrahedral selection rules appear to be strictly followed, indicating that the ion is symmetrically orientated with respect to the octahedral fields of the host lattices. A comparison of these results with those on the similar perchlorate ion previously reported at this $Symposium1$ will be given.”