title: Piperazinediium bis-(2-carboxy-pyridine-3-carboxyl-ate).
abstract: The asymmetric unit of the title salt, C(4)H(12)N(2) (2+)·2C(7)H(4)NO(4) (-) or pipzH(2) (2+)·2(py-2,3-dcH(-)), prepared by a reaction between pyridine-2,3-dicarboxylic acid (py-2,3-dcH(2)) and piperazine (pipz), contains a monoanion and half of a centrosymmetric dication. The anionic fragment individually has two intra-molecular hydrogen bonds, an almost linear O-H⋯O bond between two carboxyl-ate groups and a C-H⋯O bond between the aromatic ring and carboxyl-ate group. Other O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds are responsible for three-dimensional expansion of the structure.
authors.forename: Hossein
authors.initials: H
authors.lastname: Aghabozorg
authors.forename: Faranak
authors.initials: F
authors.lastname: Manteghi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghadermazi