Das erste gemischtvalente Oxoplumbat mit „isolierten”︁ Baugruppen: KNa7[PbIVO4][PbIIO3]

The First Mixed-valent Oxoplumbate with Isolated Anions. On KNa₇Pb^IVO₄]Pb^IIO₃] For the first time KNa₇Pb₂O₇ has been prepared by reaction of K and Na Oxides with ?PbO₂”? rsp. PbO_red e. g.: KO_0.48:NaO_0.36:?PbO₂”? = 1:7:2 (Ag-cylinders, reduced Ar-pressure, sealed in supremax-glas ampoules, 600°C, 14 d): redorange single crystals of plated shape]. The structure determination 3269 I_o(hkl), four-circle diffractometer PW 1100 (Fa. Philips), ω-scan, MoKα, R = 9.52%, R_w = 7.67%, absorption not considered] proves the space group P2₁/c with a = 1758.48(10), b = 596.76(3), c = 1066.46(8) pm, β = 90.682(8)°, Z = 4, d_x = 4.311, d_pyk = 4.28 g/cm³. The structure is characterized by isolated Pb^IVO₄] (symmetry nearly T_d) and Pb^IIO₃] groups (symmetry nearly C_3v), the latter connected by cations to double-layers. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.