Rietveld refinement of the Tutton's salt Rb-2[Cu(H2O)(6)](SO4)(2) from parallel- beam X-ray powder diffraction data

Dirubidium hexaaquacopper(II bis(sulfate), Rb-2[Cu(H2O)(6)]-(SO4)(2), is characterized by a < Cu-O > distance of 2.098 (136) angstrom. The Cu(H2O)(6) octahedron is strongly distorted because of the Jahn-Teller effect. Rb is eightfold-coordinated by six O atoms and two water molecules with an < Rb-O > distance of 3.055 (74) angstrom.