Received 7 November 2011
The asymmetric unit of the title salt, C7H10N+·C8H5O4-, consists of two 3-methylphenylammonium cations and two hydrogen phthalate anions. There are strong intramolecular O-HO hydrogen bonds in the virtually planar (r.m.s. deviations = 0.054 Å) phthalate anions. In the crystal, the cations and anions are connected via an extensive sytem of N-HO hydrogen bonds into a corrugated layer extended parallel to (001).
The title compound was investigated as part of work looking for new ferroelectric compounds. For background to ferroelectric compounds consisting of organic cations and inorganic anions, see: Fu et al. (2011); Ye et al. (2010). For a related structure, see: Kadirvelraj et al. (1996).
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: GK2431 ).
The author thanks an anonymous advisor from the Ordered Matter Science Research Centre, Southeast University, for great help in the revision of this paper.
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Kadirvelraj, R., Umarji, A. M., Robinson, W. T., Bhattacharya, S. & Row, T. N. G. (1996). Chem. Mater. 8, 2313-2323.
Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Ye, H.-Y., Cai, H.-L., Ge, J.-Z. & Xiong, R.-G. (2010). J. Appl. Cryst. 43, 1031-1035.