title: 2-Phenyl-1H-imidazol-3-ium hydrogen fumarate-fumaric acid (2/1).
abstract: The asymmetric unit of the title compound, C(9)H(9)N(2) (+)·C(4)H(3)O(4) (-)·0.5C(4)H(4)O(4), consists of one 2-phenyl-imidazolium cation, one hydrogen fumarate anion and half a fumaric acid mol-ecule, which lies on an inversion center. N-H⋯O and O-H⋯O hydrogen bonds connect the cations, anions and fumaric acid mol-ecules into sheets parallel to the (102) plane.
authors.affiliation: Institute of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang 110142,  People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Guo
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Jian-Xia
authors.initials: JX
authors.lastname: Li