The diphyllosilicate Rb2(VO)2[Si8O19]

Dirubidium divanadyl phyllooctasilicate, Rb₂(VO)₂[Si₈O₁₉], is the first known anhydrous diphyllosilicate containing V^IV. The structure consists of silicate double layers which are separated by [V₂O₈]⁸⁻ dimers and is related to that of the compounds A₂Cu₂[Si₈O₁₉] (A = Rb or Cs), although the title compound crystallizes in a noncentrosymmetric orthorhombic space group. The silicate double layers contain four tetrahedrally coordinated Si sites in general positions and 12 O sites, nine in general positions and the other three on mirror planes. The vanadyl dimers have two square‐pyramidally coordinated V sites (site symmetry m). There are two different 10‐ and 12‐fold coordinated Rb sites with site symmetry m, one of which is a split position located between the dimers in the interlayer space, while the other is in a channel within the silicate layer.