It is shown that calculated crystal lattice parameters are in accord with the values of experiment.

The effect of Si on the crystal lattice parameters, lattice volume and crystal defects of the eutectic cementite in malleable cast iron has been studied by using X ray diffractometer and TEM.

Five undetermined parameters are determined by experimental data of the total energy, three second order elastic constants and the lattice constant of the crystal at o K and zero pressure.