The crystal structure of KZr2(P04)3

The structure of KZr2(P04)3 has been determined from three-dimensional x-ray data. The crystals are rhombohedral with hexagonal nnit cell a = 8.71, c = 23.89 A, Dx = 3.22 g/cm3. The space group is R'&c and there are six formula units per unit cell. It follows from the interatomic distances that the compound is potassium trisphosphatodizirconate defined by the formula K[Zr2(P04)3]. The coordination of the zirconium atom is sixfold in the shape of octahedron. Zr—O distances are 2.06 d: 0-01 A. Six oxygen atoms are coordinated around a potassium atom in the shape of trigonal antiprism. K—O distances are 2.81 ± 0.01 A. The distances in the PO4 group do not deviate signiflcantly from the known data.Die Raumgruppe von KZr2(P04)3 ist i?3c; die hexagonale Elementarzelle hat die Gitterkonstanten a = 8,71 A, c = 23,89 A und enthalt sechs Formelein- heiten; Dx — 3,22 g/cm3. Zr ist von sechs O-Atomen im Abstand von 2,06 ± 0,01 A oktaedrisch umgeben. Auch K hat sechs O-Nachbarn in den Ecken eines in Richtung der c-Achse stark gestreckten Oktaeders; der Abstand K—O ist 2,81 d: 0,01 A. Die Abstande in der P04-Gruppe weichen nicht wesentlich von den in anderen Strukturen ab