Tris[(1,4,7,10,13,16-hexaoxacyclooctadecane)rubidium] heptaantimonide-ammonia (1/4)

The crystal structure of the title compound, [Rb(C12H24O6)](3)-[Sb-7]center dot 4NH(3), fills the gap between the already known Zintl anion ammoniates {[Cs(18-crown-6)](3)Sb-7}(2)center dot 9NH(3) [Wiesler (2007). Dissertation, Universitat Regensburg, Germany] and [K(18-crown-6)](3)Sb-7 center dot 4NH(3) [Hanauer (2007). Dissertation, Universitat Regensburg, Germany]. As in the two known compounds, the antimony cage anion in this crystal structure is coordinated by three alkali cations. The coordination spheres of each of the cations are saturated by 18-crown-6 molecules. The ammonia molecules of crystallization are situated between the crown ethers. The neutral, molecular [Rb(18-crown-6)](3)Sb-7 units are interconnected by multiple dipole-dipole interactions between ammonia and 18-crown-6.