Ammonium 1-hydroxy-2-naphthoate

The title compound, NH4 +·C11H7O3 −, was obtained by slow evaporation of a 30% ammonia solution of 1-hydroxy-2-naphthoic acid. The crystal structure is stabilized by intermolecular N—H⋯O hydrogen bonds, forming layers parallel to the bc plane.

The title compound, NH 4 + ÁC 11 H 7 O 3 À , was obtained by slow evaporation of a 30% ammonia solution of 1-hydroxy-2naphthoic acid. The crystal structure is stabilized by intermolecular N-HÁ Á ÁO hydrogen bonds, forming layers parallel to the bc plane.

Experimental
Crystal data
The compound consists of discrete 1-hydroxynaphthalene-2-carboxylate anions and ammonium cations (Fig. 1). The anion is substantially planar with a mean deviation of 0.015 (3) Å. The crystal structure is stabilized by intermolecular N-H···O hydrogen bonds (Table 1), forming layers parallel to the bc plane ( Fig. 2).

Experimental
Single crystals of the title compound were obtained by slow evaporation of a 30% ammonia solution of 1-hydroxynaphthalene-2-carboxylic acid in air.

Refinement
Ammonium H atoms were located from a difference Fourier map and refined isotropically, with N-H distances restrained to 0.90 (1) Å, H···H distances restrained to 1.43 (2) Å, and with U iso (H) values fixed at 0.08 Å 2 . All other H atoms were placed in idealized positions and constrained to ride on their parent atoms with C-H distances of 0.93 Å, O-H distance of 0.82 Å, and with U iso (H) set at 1.2U eq (C) or 1.5U eq (O). Fig. 1. The structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme. The intramolecular hydrogen bond is shown as a dashed line.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.
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.