A neutron diffraction and isotopic substitution measurement of the structure of liquid Cu2Se

The partial structure factors and pair distribution functions of liquid Cu2Se have been determined by neutron diffraction with isotopic substitution. The structure shows characteristics typical of those of an ionic 2:1 melt consisting of Cu+ and Se2- ions with the cations moving through a more ordered Se2- sub-structure. A detailed comparison has been made with recent results obtained for liquid Ag2Se. The structure is similar although there is no evidence of the double peak structure in the cation-cation partial structure factor. S-CuCu(Q), as has been found in S-AgAg(Q) for liquid Ag2Se and, to a more limited extent, for liquid Ag2Te. There is also less order in the Se2- sub-structure based on a comparison of S-SeSe(Q) and the Bhatia-Thornton concentration-concentration structure factor, S-CC (Q), for the two liquids.