In the present paper, we have study the of zone-centre phonon modes of mixed chromite spinels using a proposed theoretical model. In this model, we have calculated the three bond stretching, three bond-bending interactions and three effective dynamical charges. Using the above calculated model parameters, we have calculated the composition dependent zone-centre phonon modes for mixed chromite spinelsCdCr2Se4(1-x)S4x, Zn1-xCdxCr2S4, CdxZn1-xCr2Se4 and HgxZn1-xCr2Se4. We find good agreement with the experimental and theoretical results available in the literature.
Keywords: zone-centre, Raman, infrared, spinels