Crystal structure of guanidinium squarate dihydrate: C₄O₄· 2C(NH₂)₃· 2H₂O

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