PREPARATION AND CRYSTAL-STRUCTURE OF GUANIDINIUM CYCLODODECAPHOSPHATEHEXAHYDRATE - [C(NH2)(3)]12P12O36-CENTER-DOT-6H(2)O

The title compound was prepared by ion exchange from the potassium sal t, K12P12O36. 19/2H(2)O. It represents a second new structural type of [P12O36](12-) ring anions. This sparingly water soluble salt is hexag onal, space group P6(3), with Z=2 and the cell dimensions: a=15.904(7) , c=16.67(2) Angstrom. The crystal structure was solved by direct meth ods and refined to a final R value of 0.050. The ring anion is located around the threefold axis and hence has a threefold symmetry. The sta cking of the rings creates large channels, parallel to the c direction , in which the guanidinium groups and the water molecules are located. Three of the six independent guanidinium groups are located on the th reefold axes. The cohesion of the structure is performed by the numero us H-bonds generated by the organic cations and the water molecules.