Rb(2)Sb(4)O(11).

The title compound, dirubidium tetra-anti-monate(V), Rb(2)Sb(4)O(11), has been synthesized by flux reaction. It is isotypic with known A(2)Sb(4)O(11) (A = K, Cs) structures and consists of an (Sb(4)O(11))(2-) skeleton and two Rb atoms as charge-compensating cations. Distorted SbO(6) octa-hedra share edges and corners, resulting in a layered assembly. Alternate stacking of the layers along the c axis leads to the formation of tunnels. The Rb(+) ions, surrounded by nine and ten O atoms, respectively, are located in these tunnels. Some atoms in the structure are on special positions of m symmetry (two Sb atoms, both Rb atoms and four O atoms) and 2 symmetry (one O atom).