Tris(2-carbamoylguanidinium) hydrogen fluorophosphonate fluorophosphonate monohydrate

The title structure, 3C2H7N4O+·HFPO3 −·FPO3 2−·H2O, contains three independent 2-carbamoylguanidinium cations, one fluorophosphonate, one hydrogen fluorophosphonate and one water molecule. 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 molecule, the hydrogen fluorophosphonate and fluorophosphonate anions. N—H⋯O hydrogen bonds between the guanylurea molecules that interconnect the molecules within each layer are strong. The layers are interconnected by strong and weak O—H⋯O hydrogen bonds between the anions and water molecules, respectively. Interestingly, the configuration of the layers is quite similar to that observed in 2-carbamoylguanidinium hydrogen fluorophosphonate [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.