Synthesis and characterization of alkali-metal tin(II) phosphates: Na(10)Sn(31)(HPO(4))(6)(P(2)O(7))(6)(PO(4))(12) and K(2)SnP(2)O(7)

Abstract

Two new alkali-metal tin(II) phosphates - Na(10)Sn(31)(HPO(4))(6)(P(2)O(7))(6)(PO(4))(12) (1) and K(2)SnP(2)O(7) (2) - were synthesized by high-temperature reactions and structurally characterized by single-crystal X-ray diffraction. Na(10)Sn(31)(HPO(4))(6)(P(2)O(7))(6)(PO(4))(12) crystallized in the noncentrosymmetric space group P-62c (No. 190) with a = 9.6445(1) angstrom, b = 9.6445(1) angstrom, c = 34.059(6) angstrom, V = 2743.6(7) angstrom(3) and Z = 1. K(2)SnP(2)O(7) crystallized in the monoclinic space group P2(1)/n with a = 9.856(3) angstrom, b = 6.7244(1) angstrom, c = 12.225(3) angstrom, beta = 108.240(5)degrees, V = 769. 5(3) angstrom(3) and Z = 4. Both structures exhibit a novel open-framework structure. The crystal structure of 1 contains SnO(3) and SnO(4) polyhedra sharing comers with [HPO(4)](2-), [PO(4) ](3-) and [P(2)O(7)](4-) groups, which form tunnels of six rings filled with Na(+) cations and parallel to the c-axis, which are connected via O-Sn-O bridges to form a three-dimensional open framework. The crystal structure of 2 contains SnO(4) seesaw polyhedra sharing comers with diphosphate groups to form a three-dimensional [SnP(2)O(7)](2-) framework that exhibits a tunnel structure of 10- and 12- membered rings expanding along [011] and [100] with four arrays of K(+) cations located in channels of the framework. (c) 2008 Elsevier Masson SAS. All rights reserved.