Dipole–Dipole Interactions in Tungstates

The vibrational spectra of divalent metal tungstates of the form MWO₄, where M = Ba, Sr, Ca, or Zn, have been analyzed in terms of dipole–dipole interactions between adjacent tungstate ions. The van der Waals potential constants determined are of the order of ${\text{(13\hspace{0.17em}−\hspace{0.17em}110)\hspace{0.17em}×\hspace{0.17em}10}}^{\text{−60}}{\mathrm{erg·cm}}^6$ and approximate those for alkali halides. The present analysis allows for the interpretation of vibrational levels in ZnWO₄, which is of a lower symmetry than the scheelites and not previously subject to such characterization.