Phonons and crystalline structures of Hg1?xCdxSe alloys (0 ? x ? 0.5) were studied by Raman spectroscopy and X-ray powder diffraction patterns at 298K. The crystalline alloys were prepared by a special combination of synthesis and the Bridgman method. Experimental data showed a face-centered cubic structure, F43m (No. 216), for all samples, exhibiting a linear dependence for Cd molar fraction, x, for cell parameters, a, and the mass densities, ?. Phonon frequencies were analyzed using the Romevi-Romevi model for phonons in multicomponent alloys, obtaining a fair agreement with experimental data. Furthermore, an algorithm to implement the Romevi-Romevi model is proposed.