CRYSTAL-STRUCTURE OF GUANIDINIUM SQUARATE DIHYDRATE - C4O4-CENTER-DOT-2C(NH2)(3)CENTER-DOT-2H(2)O

The crystal and molecular structure of guanidinium squarate dihydrate, C4O4 . 2 C(NH2)(3) . 2 H2O, has been determined by X-ray analysis. Ea ch squarate dianion is linked by bidentate hydrogen bonds to two guani dinium cations. The origin molecule is nearly coplanar with the molecu le generated by the glide plane and translated along the ac plane diag onal; they form a wide ribbon, which is repeated parallel, but shifted down of 1.316(7) Angstrom, by the translation along the ac plane diag onal. This arrangement gives rise to a bidimensional network resemblin g a sort of thick, undulated layer, which is repeated by the a transla tion at a distance of 3.464(7) Angstrom. The water molecules of crysta llization, located between these layers, provide the interlayer connec tion and play a fundamental role in the stabilisation of the crystal s tructure.