4-Carboxyanilinium chloride

In the title salt, C7H8NO2 +·Cl−, the cation and anion are linked by an O—H⋯Cl hydrogen bond. The three-dimensional crystal structure is stabilized by N—H⋯O and N—H⋯Cl hydrogen bonds.

In the title salt, C 7 H 8 NO 2 + ÁCl À , the cation and anion are linked by an O-HÁ Á ÁCl hydrogen bond. The three-dimensional crystal structure is stabilized by N-HÁ Á ÁO and N-HÁ Á ÁCl hydrogen bonds.

Comment
We intended to prepare a cerium(III) complex of p-aminobenzoic acid. However, we obtained crystals of the title salt, and we report here its crystal structure.
In the title salt, the asymmetric unit consists of one p-aminobenzoic acid cation and one chloride anion (Fig. 1).
The hydrogen bonds listed in Table 1 result in a crystal structure generated by inversion and glide symmetry (Fig. 2).

Experimental
To a solution containing p-aminobenzoic acid (1.37 g, 10 mmol) in ethanol (30 ml), a solution of cerium(III) chloride (1.24 g, 5 mmol) in methanol (15 ml) was added with stirring for 2 h at 323 K, and then the solution was filtered. Colourless crystals suitable for X-ray crystal structure analysis were obtained from the filtered solution over a period of two weeks.

Refinement
All H atoms were located in a difference Fourier map and refined freely; Csp 2 -H = 0.87 (6) Fig. 1. The asymmetric unit of the title structure. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms are shown as spheres of arbitrary radius.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.