AbstractRaman and infrared spectra of a series of double chromates of the type Lnk(CrO4)2, with Ln = La, Pr, Nd, Sm, were recorded and discussed with the aid of a factor group analysis. These substances constitute the first example showing the intercalation ofv1betweenv3components in crystalline chromates. The spectroscopic results confirm again the structural differences between these chromates and PbCrO4(synthetic crocoite), which was also investigated for comparison.