The infrared and Raman spectra of three tetrametaphosphatesM₂P₄O₁₂ (M = Fe, Ni, Zn) have been recorded and analysed. A factor group model has been used to interpret the spectra of Fe₂P₄O₁₂ and Ni₂P₄O₁₂. A free ion model could explain the Zn₂P₄O₁₂ spectra. The frequencies have been assigned on the basis of characteristic vibrations of PO₂²⁻ and P-O-P groups. The P₄O₁₂⁴⁻ ion is found to haveC_i symmetry in Fe₂P₄O₁₂ and Ni₂P₄O₁₂ andC₂₄ in Zn₂P₄O₁₂. The ion in Fe₂P₄O₁₂ is more distorted than in the other two.

The IR and polarized Raman spectra of SrC₄H₄O₆ · 3H₂O have been recorded and analysed. The factor group analysis of the divalent tartrate ion has been carried out on the basis of C₂ symmetry. As the ion possesses lower symmetry in the crystal, splittings have been observed for the different vibrational modes. Separate bands in the bending region of water suggest the existence of three crystallographically different water molecules in the crystal, which is confirmed by deuterium substitution.