Das erste quaternäre Oxostannat mit „Inselstruktur”︁: RbNa3[SnO4]

The First Quaternary Oxostannate with Isolated Anion Structure: RbNa₃[SnO₄] For the first time colourless single crystals of RbNa₃SnO₄ which are isotypic with NaLi₃SiO₄ and NaLi₃GeO₄ [2] have been prepared by heating e.g. a well ground mixture of RbSn and Na₂O₂ [Rb : Na = 1 : 4.0; 750°C; 21 d; Ni-tube]. The crystal structure was solved by four-cycle-diffractometer data [Siemens AED2; 1801 I₀(hkl); space group I4₁/a; Z = 16; a = 1279.57, c = 1510.85 pm; R = 5.7%; R_w = 4.4%]. Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, are calculated. The isotypism of the compounds mentioned above is compared graphically.