Synthese und Kristallstruklur von Triblei-Diphosphato-Borat-Phosphat, eine Verbindung mit einem 1 ∞[(PO4)2BPO4]6–-Anion / Synthesis and Crystal Structure of Trilead-Diphosphato-Borate-Phosphate, a Compound with a 1 ∞[(PO4)2BPO4]6–-Anion

Single crystals of Pb3[(PO4)2BPO4] were obtained by melting B2O3, P2O3 and PbO at 960 °C. The structure is related to the Ba3[(PO4)2BPO4] type. X-ray investigations on single crystals led to the space group Pbca - D15 2h (Nr. 61) with a = 694.6(1), b = 1419.9(3), c = 2111.6(2) pm, Z = 8 . Boron and phosphorus are tetrahedrally coordinated by oxygen. The polyhedra form one-dimensional infinite helices that contain two additional PO4 groups connected to the BO4-unit. Lead is eightfold coordinated by oxygen. The relation to the crystal structure of Ba3[(PO4)2BPO4] is discussed.