title: 4,4'-Bipyridine-pyridine-3,5-dicarb-oxy-lic acid (3/4).
abstract: In the title compound, 3C(10)H(8)N(2)·4C(7)H(5)NO(4), the asymmetric unit contains two mol-ecules of pyridine-3,5-dicarb-oxy-lic acid and one mol-ecule of 4,4'-bipyridine in general positions together with one mol-ecule of 4,4'-bipyridine lying across a centre of inversion, thus giving a 4:3 molar ratio of pyridine-3,5-dicarb-oxy-lic acid to 4,4'-bipyridine. The dihedral angle between the bipyridine rings on general positions is 21.2 (2)°. These mol-ecular units are linked by O-H⋯N hydrogen bonds forming an extended two-dimensional framework in the crystal.
authors.forename: Sheng-Bo
authors.initials: SB
authors.lastname: Liu
authors.forename: Chao
authors.initials: C
authors.lastname: Xu
authors.forename: Taike
authors.initials: T
authors.lastname: Duan
authors.forename: Qun
authors.initials: Q
authors.lastname: Chen
authors.forename: Qian-Feng
authors.initials: QF
authors.lastname: Zhang
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Acta Crystallogr Sect E Struct Rep Online. 2008 Dec 17;65(Pt 1):o153
references.pmid: 21581611
references.citation: Acta Crystallogr Sect E Struct Rep Online. 2010 Nov 27;66(Pt 12):o3308
references.pmid: 21589586