STRUCTURE, THERMAL-BEHAVIOR AND IR INVESTIGATION OF A NEW ORGANIC CYCLOHEXAPHOSPHATE

Physicochemical properties of the bis[1-(2-ammoniumethyl) piperazinium ] cyclohexaphosphate hexahydrate are discussed on the basis of X-ray c rystal structure investigation. [C6H18N3]2P6O18. 6H(2)O is triclinic, <P(1)over bar>, with a=9.714(2) Angstrom, b=10.538(2) Angstrom, c=8.09 5 Angstrom, alpha=87.88(2)degrees, beta=93.48(2)degrees, gamma=83.20(1 )degrees, and Z=1. The structure has been solved using direct methods and refined to a reliability R factor of 0.0307 for 2291 reflections. The compound is characterized by infinite layers of inorganic polyanio ns approximately parallel to the (001) planes. Organic cations are san dwiched between these layers. OW-H ... O and N-H ... O hydrogen bonds link P6O18 groups, respectively, in a layer and in successive layers a s to build a framework in a three-dimensional way. Two water molecules leave this compound at room temperature giving a stable tetrahydrate phase. The structure reorganization is discussed on the basis of OW H- bonds by TG-DTA and DSC thermal analyses. The reported IR study is sup ported by a detailed theoretical group analysis applied to P6O18 with D(6h)ideal local symmetry. (C) 1996 Academic Press, Inc.