title: Dimethyl-ammonium guanidinium naphthalene-1,5-disulfonate.
abstract: The asymmetric unit of the title salt, CH(6)N(3) (+)·C(2)H(8)N(+)·C(10)H(6)O(6)S(2) (2-), consists of one dimethyl-ammonium cation, one guanidinium cation, and two half naphthalene-1,5-disulfonate anions, which lie on inversion centers. N-H⋯O hydrogen bonds link the cations and anions into layers parallel to the ab plane. The layers have a sandwich-like structure, with the sulfonate groups and cations forming outer slices and the naphthalene ring systems inside.
authors.affiliation: Ordered Matter Science Research Center, Southeast University, Nanjing 211189,  People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wei