Synthesis and crystal structure of (1,6-NH3C6H12NH3)2(1-NH3C10H7)2P6O18.2H2O

Abstract

Synthesis and complete structural characterization by X-ray diffraction, DTA, GTA and IR are given for a new cyclohexaphosphate: (1,6-NH₃C₆H₁₂NH₃)₂ (1-NH₃C₁₀H₇)₂P₆O₁₈.2H₂O. This compound is monoclinic P2₁/c with the following unit-cell parameters: a = 11.861(2)Å, b = 10.104(1)Å, c = 19.664(6)Å, β = 96.44(2)°, and Z = 2. The crystal structure has been solved and refined to R = 0.033 using 3928 independent reflections. The atomic arrangement can be described as layer organisation. Layers built by P₆O₁₈ ring anions and water molecules spread in the plans (100). Between these layers are located the organic groups which form hydrogen bonds with oxygen atoms of P₆O₁₈ rings and water molecules. Geometrical characteristics of hydrogen bonds are described. The reported IR study is supported by a delaited theoretical group analysis applied to P₆O₁₈ with D_6h ideal local symmetry.