FH···F hydrogen bond in diphenylguanidinium hydrogen bifluoride

The crystal structure of C13H14N3+FHF− is reported. The structure contains the strong hydrogen-bonded system, the bifluoride anion FH···F−. The geometry of this anion deviates significantly from linearity but has the H atom in an approximate centered position. The F···F distance is 2.293(3) Å, considerably less than twice the van der Waals radius of fluorine, as expected from a very strong hydrogen bond. the phenyl rings of the diphenylguanidinium counter ion of the bifluoride anion is oriented syn to the unsubstituted N atom of the guanidine group, the other adopts an anti conformation. ions and cations are held together by a layered two-dimensional network of hydrogen bonds. Both NH and NH2 groups of the cation are donors towards the fluoride ions, exhausting the potential of diphenylguanidine for hydrogen bonding.