AbstractUsing the reduction of tin oxides with the elemental alkaline metals rubidium and cesium, stannide stannates have been synthesized which contain Zintl anions [Sn4]4— (i.e. Sn—I) and isolated oxostannate ions [SnO3]4— (i.e. Sn+II) together with further oxide ions for charge compensation. The crystal structures of the three compounds A23.6Sn7.4O13.2 = A23.6[Sn4][SnO3]3.4[O]3 (A = Rb 1a: monoclinic, P21/c, a = 2174.2(6), b = 1137.0(6), c = 2373.6(6) pm, β = 116.11(2)°, Z = 4, R1 = 0.056; A = Cs 1b: monoclinic, P21/c, a = 2042.6(6), b = 1185.4(3), c = 2481.1(7) pm, β = 97.06(2)°, Z = 4, R1 = 0.075) and Cs48Sn20O21 = Cs48[Sn4]4[SnO3]4[O]7[O2] (2 monoclinic, P2/c, a = 1701.8(3), b = 877.4(2), c = 4556.9(7) pm, β= 101.47(1)°, R1 = 0.093) have been determined on the basis of single crystal data. The transparency of the compounds allowed the recording of raman spectra of the anion [Sn4]4—. The 119Sn Moessbauer spectrum of the rubidium compound shows a singulet in good agreement with RbSn, overlapping a doublet caused by Sn2+ in the asymmetrical environment of the strongly electronegative oxygen ligands of SnO.