In the third part of this study, a theoretical model for the crystal structure of Cr₂N was derived based on the static concentration waves (SCWs) method, and discussed in comparison with other E-type ordering models suggested in Fe-N system. The modified occupation probability function (OPF) for describing the distribution of nitrogen atoms in Cr₂N superstructure was calculated using the superlattice reflections found in the previous study, and could be expressed as: n(r)=c－1/6η₁cos2πz＋4/3η₃cos2/3π(x＋y＋3z). And, this OPF function has four components depending on the distribution of nitrogen atoms within Cr2N superstructure: n₁=c－1/6η₁＋4/3η₃,n₂=c＋1/6η₁－4/3η₃,n₃=c－1/6η₁－2/3η₃and n₄=c＋1/6η₁＋2/3η₃.