The structure of diguanidinium pentafluoroantimonate, (CH6N3)(2)[SbF5]
, has been determined and refined to R = 2.3%. The SbF52- anion is a d
istorted rectangular pyramid with F atoms at the vertices and a mirror
plane C-s through atoms F(1) and Sb. The two inequivalent guanidinium
ions are planar and display only mirror symmetry, not C-3, as expecte
d. The crystal structure consists of two sets of guanidinium sheets li
nked by N-H...F hydrogen bonds to pentafluoroantimonate ions.