The Warren-Cowely Parameter (WCP) for short range solution order is defined as:
$$\mathrm{WCP}_{ij} = 1 - \frac{Z_{ij}}{x_j \cdot Z_i}$$

where $$Z_{ij}$$ is the partial Coordination Number (CN) of j atoms around i, $$Z_{i}$$ is the total CN around i, and $$x_{j}$$ is the nominal composition of j.

Consider a two component solution of $$\ce{A}$$ and $$\ce{B}$$. If $$\mathrm{WCP}>0$$, like neighbors are preferred, If $$\mathrm{WCP}<0$$, unlike neighbors are preferred.

If both of $$\mathrm{WCP}_{AA}$$ and $$\mathrm{WCP}_{BB}$$ are positive, which one is preferred?

• Could you clarify what $Z_{ij}$ and $x_j$ are in your equations? Does your definition match the one in this paper: deepblue.lib.umich.edu/bitstream/handle/2027.42/29021/… – Tyberius Feb 18 '20 at 16:27
• Dear @Tyberius I have updated my question, and added the definitions – user89031 Feb 18 '20 at 17:09
• @Tyberius do you not have any idea about this question? I checked the parameter with the definition in the paper you introduced, they are identical – user89031 Feb 25 '20 at 23:33
• I do not know for sure. It could be that $WCP_{AB} is what actually matters.$WCP_{AA}$and$WCP_{BB}\$ both positive seems to me like it implies that both components prefer like neighbors. I had hoped clarifying your question and introducing some terminology for people who aren't familiar (like myself) would encourage an answer. – Tyberius Feb 25 '20 at 23:48