CRYSTAL-STRUCTURE OF GUANIDINIUM CYCLODECAPHOSPHATE TETRAHYDRATE

[C(NH2)(3)]10P10O30.4 H2O is the first organic-cation cyclodecaphospha te elaborated and structurally charaterized by single-crystal X-ray di ffraction methods. It crystallizes in the triclinic system, P $($) ove r bar$$ 1, with Z = 1 and the following unit-cell dimensions: a = 12.1 92(8) Angstrom, b = 14.083(9) Angstrom, c = 9.317(6) Angstrom, alpha = 91.25(3)degrees, beta = 103.61(3)degrees, gamma = 71.22(2)degrees. Th e crystal structure was solved using 8862 unique reflections with a fi nal R value of 0.032. The centrosymmetrical P10O30 rings are interconn ected through the organic entities and the water molecules by a very i ntricated network of strong hydrogen bonds. The high stability of the title compound can probably be explained by the strength and the large number of these hydrogen bonds and by its low hydration state.