RbAu(SeO4)2: First Structure Determination of a Ternary Gold Selenate

Yellow single crystals of RbAu(SeO₄)₂ were obtained upon evaporation of a solution prepared from the reaction of elemental gold and Rb₂CO₃ with conc. selenic acid. In the crystal structure (monoclinic, C2/m, Z = 2, a = 1078.7(4), b = 522.7(1), c = 739.3(2) pm, β = 116.45(2)°) Au³⁺ is in square planar coordination of oxygen atoms which belong to four SeO₄^2- ions. According to [Au(SeO₄)_4/2]^- anionic chains are formed which are connected by the Rb⁺ ions. The latter are surrounded by two chelating and six monodentate selenate groups leading to a CN of 10.