Tris(2-carbamoylguanidinium) hydrogen fluoro-phospho-nate fluoro-phospho-nate monohydrate.

The title structure, 3C(2)H(7)N(4)O(+)·HFPO(3) (-)·FPO(3) (2-)·H(2)O, contains three independent 2-carbamoylguanidinium cations, one fluoro-phospho-nate, one hydrogen fluoro-phospho-nate and one water mol-ecule. There are three different layers in the structure that are nearly perpendicular to the c axis. Each layer contains a cation and the layers differ by the respective presence of the water mol-ecule, the hydrogen fluoro-phospho-nate and fluoro-phospho-nate anions. N-H⋯O hydrogen bonds between the guanylurea mol-ecules that inter-connect the mol-ecules within each layer are strong. The layers are inter-connected by strong and weak O-H⋯O hydrogen bonds between the anions and water mol-ecules, respectively. Inter-estingly, the configuration of the layers is quite similar to that observed in 2-carbamoylguanidinium hydrogen fluoro-phospho-nate [Fábry et al. (2012). Acta Cryst. C68, o76-o83]. There is also present a N-H⋯F hydrogen bond in the structure which occurs quite rarely.