ABSTRACT
Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 â¶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.
ABSTRACT
A new compound, dipotassium holmium(III) phosphate(V) tungstate(VI), K(2)Ho(PO(4))(WO(4)), has been obtained during investigation of the K(2)O-P(2)O(5)-WO(3)-HoF(3) phase system using the flux technique. The compound is isotypic with K(2)Bi(PO(4))(WO(4)). Its framework structure consists of flat (∞) (2)[HoPO(4)] layers parallel to (100) that are made up of (∞) (1)[HoO(8)] zigzag chains inter-linked via slightly distorted PO(4) tetra-hedra. WO(4) tetra-hedra are attached above and below these layers, leaving space for the K(+) counter-cations. The HoO(8), PO(4) and WO(4) units exhibit 2 symmetry.
