Bis(2,9-dimethyl-1,10-phenanthrolin-1-ium) hydrogen (S,S)-tartrate nona­hydrate

The asymmetric unit of the title compound, 2C(14)H(13)N(2) (+)·2C(4)H(5)O(6) (−)·9H(2)O, contains two cations and two anions in addition to nine mol­ecules of water. Each of the hydrogen tartrate anions is hydrogen bonded to itself by translation along [100] in a head-to-tail fashion via a short hydrogen bond with donor–acceptor distances of 2.473 (4) and 2.496 (4) Å. A large number of inter­molecular O–H⋯O, N—H⋯O and C–H⋯O hydrogen-bonding inter­actions, as well as π–π stacking [centroid–centroid distances in the range 3.642 (3) to 3.866 (3) Å], play an important role in the crystal structure.