Vibrational (IR absorption and spontaneous Raman) spectra of mixed fluorido
phosphates Na3Cr2(PO4)(2)F-3, Na5Cr(PO4)(2)F-2, KCrPO4F, and KFePO4F are st
udied. The region of fluorine vibration modes is established. Their correla
tion to the crystal structures and metal-fluorine interatomic distances is
demonstrated.