Experimental

R factor = 0.040; wR factor = 0.110; data-to-parameter ratio = 9.5. In the cation of the title salt {systematic name: 4-[bis(4-fluorophenyl)methyl]-1-[(2E)-3-phenylprop-2-en-1-yl]pipera-zin-1-ium pyridine-4-carboxylate}, C26H27F2N2 +C6H4NO2, the piperazine ring is in a slightly distorted chair conforma-tion. The dihedral angle between the mean planes of the fluoro-substituted benzene rings is 81.9 (1) and these benzene rings form dihedral angles of 6.5 (1) and 87.8 (1) with the phenyl ring. In the crystal, a single N—H O hydrogen bond links the cation and the anion. In addition, weak C—H O hydrogen bonds and – stacking inter-actions involving one of the fluoro-substituted benzene rings and the phenyl ring, with a centroid–centroid distance of 3.700 (7) Å, link molecules along [100]. Related literature For the bioligical activities of flunarizine, see: Amery (1983); Holmes et al. (1984). For related structures, see: Kavitha et al. (2013a,b,c,d). For puckering parameters, see Cremer & Pople (1975). For standard bond lengths, see: Allen et al. (1987)