Date Published: June 01, 2012
Publisher: International Union of Crystallography
Author(s): Wen-Ni Zheng.
In the title compound, 2C6H4N2·C2H2O4, the oxalic acid molecule lies about an inversion center. The pyridine ring of the pyridine-4-carbonitrile molecule is almost planar, the largest deviation from the least-squares plane being 0.006 (1) Å; the nitrile N atom deviates from this plane by 0.114 (1) Å. In the crystal, the oxalic acid molecules and the pyridine-4-carbonitrile molecules form stacks. Neighboring molecules within the stacks are related by translation in the a direction, with interplanar distances of 3.183 (1) and 3.331 (2) Å, respectively. Each oxalic acid molecule forms strong O—H⋯N hydrogen bonds with two molecules of pyridine-4-carbonitrile. Besides this, there are also weak C—H⋯O interactions.
For the structures and ferroelectric properties of related compounds, see: Fu et al. (2011a ▶,b ▶,c ▶); Dai & Chen (2011 ▶); Xu et al. (2011 ▶); Zheng (2011 ▶). For standard bond lengths, see: Allen et al. (1987 ▶).