Synthesis and crystal structures of zirconium phosphate fluorides with new 2D and 3D structure types

Three new zirconium phosphate fluorides, [amH(2)](0.5) [Zr-2(PO4)(HPO4)(2)F-2]. 0.5H(2)O (1), [amH(2)](1.5)[Zr-3(PO4)F-3(6)]. 1.5H(2)O (2) (am = trans-1,4-diaminocyclohexane for 1 and 2), and [amH(2)](0.5)[Zr-2(PO4)(3)(HPO4)F-2]. 1.5H(2)O (am = 2,2-dimethyl-1,3-diaminopropane) (3), were synthesized under hydrothermal conditions and structurally characterized. Zr is octahedrally coordinated in all three structures. In 1, the octahedra consist of ZrO6 and ZrO4F2 units. Compound 2 is made exclusively of ZrO4F2. In 3, there are three different types of Zr-octahedra, namely, ZrO6, ZrO5F, and ZrO4F2. The Zr octahedra and PO, tetrahedra are connected via non-OH oxygen atoms. In 1 and 2, all F atoms are terminal, whereas in 3, one of the two F atoms bridges between the ZrO5F and ZrO4F2 octahedra. In structures 1 and 2 with higher F/Zr ratios, two-dimensional inorganic networks exist, The inorganic sheets are connected by the protonated templates via N-H ... F and in 1 additionally by O-H ... F hydrogen bonds. In 3, the lower F/Zr ratio results in the formation of a three-dimensional inorganic framework with characteristic double channels in which the highly disordered templates are located. The existence of several structure types in the ZrPOF-n family is discussed on the basis of different template geometry and F/Zr ratios. (C) 2000 Academic Press.