Abstract: A theoretical investigation of the crystal lattice of compounds CdTe and MnTe belonging to the II-VI family when they are alloyed by introducing Zn and Mn atoms, respectively, has been performed. For this purpose the tetrahedral model has been chosen in order to calculate the energy of deformation and the bond lengths. The model considers that: the microscopic structure is zinc blend. The chemically ordered sublattice is deformed. The chemically disordered sublattice is undeformed. Cd1-xMnxTe form the zinc blend structure until x = 0.70. The obtained results for Cd1-xZnxTe show that there is no angle tilt due to the alloying phenomenon, which is confirmed otherwise by the experiments. The application of the model to Cd1-xMnxTe until x = 0.70 showed the same results.