Site Preference and Ordering Induced by Au Substitution in the γ-Brass Related Complex Au-Cr-Zn Phases.

The crystal chemistry of the ternary Au-Cr-Zn alloy was studied by means of synthesis, single crystal X-ray diffraction, and electron structure calculations. While the compound CrZn∼17 represents the binary end-point of the homogeneity range, the inclusion of Au proves to be very site specific, and at the limiting composition Au10Cr4Zn89 the structure is completely ordered. The crystallographic site occupancy pattern calculated by the Local Density Approximation (LDA)-Density Functional Theory (DFT) parametrized extended Hückel (eH) Mulliken charge populations in Au10Cr4Zn89 agrees very well with the experimentally found site occupancy pattern.