title: Bis[(E)-4-(hydroxy-imino-meth-yl)pyridinium] oxalate.
abstract: The formula unit of the title compound, 2C(6)H(7)N(2)O(+)·C(2)O(4) (2-), comprises two symmetry-equivalent 4-(hydroxy-imino-meth-yl)-pyridinium cations on general positions, linked through hydrogen bonding via an oxalate anion that resides on a crystallographic centre of symmetry. The crystal structure consists of infinite chains of cations and oxalate anions directed by O-H⋯O and multicentre N-H⋯O inter-molecular hydrogen-bonding inter-actions.
authors.forename: Rüdiger W
authors.initials: RW
authors.lastname: Seidel
authors.forename: Manuela V
authors.initials: MV
authors.lastname: Winter
authors.forename: Iris M
authors.initials: IM
authors.lastname: Oppel