Received 19 April 2012
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-HN hydrogen bonds with two molecules of pyridine-4-carbonitrile. Besides this, there are also weak C-HO 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).
Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: YK2054 ).
This work was supported by a start-up grant from Southeast University, China.
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.
Dai, J. & Chen, X.-Y. (2011). Acta Cryst. E67, o287.
Fu, D.-W., Zhang, W., Cai, H.-L., Ge, J.-Z., Zhang, Y. & Xiong, R.-G. (2011c). Adv. Mater. 23, 5658-5662.
Fu, D.-W., Zhang, W., Cai, H.-L., Zhang, Y., Ge, J.-Z., Xiong, R.-G. & Huang, S. P. D. (2011a). J. Am. Chem. Soc. 133, 12780-12786.
Fu, D.-W., Zhang, W., Cai, H.-L., Zhang, Y., Ge, J.-Z., Xiong, R.-G., Huang, S. P. D. & Nakamura, T. (2011b). Angew. Chem. Int. Ed. 50, 11947-11951.
Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Xu, R.-J., Fu, D.-W., Dai, J., Zhang, Y., Ge, J.-Z. & Ye, H.-Y. (2011). Inorg. Chem. Commun. 14, 1093-1096.
Zheng, W.-N. (2011). Acta Cryst. E67, m344.