Structural modification and optical reflectivity of new gold–indide intermetallic compounds

The gold–indide SrAu3.36(2)In4.64 contains a novel 3D Au/In network, which can be described in terms of complex ∞3[Au,In]82− polyanions with strontium atoms filling hexagonal cages that are part of highly condensed infinite channels. This new intermetallic compound represents a small decrease in the indium content, i.e., as compared to SrAu3.76(4)In4.24, and results in a significant orthorhombic to monoclinic structural transformation. Electronic structure calculations by Linear Muffin-Tin-Orbital (LMTO) methods show that Au–In interactions are predominant in its structural stabilization. UV–vis measurements show a generally lower reflectivity and higher absorption, as compared to elemental Au.