Zum System K2O/PbO. Zur Kenntnis von K2Pb2O3

On the System K₂O/PbO: The Crystal Structure of K₂Pb₂O₃ Orange-coloured single crystals of K₂Pb₂O₃ crystallize by means of 4-circle-Diffractometer data (237 of 238 possible hkl, R = 5.9₉%, MoKα) cubic with a = 8.41₉ Å, Z = 4, in space group I2₁3?T⁵, parameter see text. We find a superstructure of the perovskite type of structure, where, concerning the formula KPbO_3/2, half of the O^2? ions are omitted systematically, without loosing the 3-Dimensional arrangement of order. Pb²⁺ is surrounded by 3 K⁺ by 6 O^2? and O^2? by 2 Pb²⁺ and 4 K⁺. The Madelung Part of the Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, are calculated and discussed.