Acta Crystallographica Section C

Structural Chemistry

Volume 70, Part 3 (March 2014)

organic compounds

sk3526 scheme

Acta Cryst. (2014). C70, 323-325    [ doi:10.1107/S2053229614002447 ]

The structural properties of a noncentrosymmetric polymorph of 4-amino­benzoic acid

R. Benali-Cherif, R. Takouachet, E.-E. Bendeif and N. Benali-Cherif

Abstract: The crystal structure of a polymorph of 4-amino­benzoic acid (PABA), C7H7NO2, at 100 K is noncentrosymmetric, as opposed to centrosymmetric in the structures of the other known polymorphs. The two crystallographically independent PABA mol­ecules form pseudocentrosymmetric O-H...O hydrogen-bonded dimers that are further linked by N-H...O hydrogen bonds into a three-dimensional network. The benzene rings stack in the b direction. The CO2 moieties are bent out slightly from the benzene ring plane.

CCDC reference: 984821

Formula: C7H7NO2

Keywords: crystal structure; 4-amino­benzoic acid; PABA; polymorphism; noncentrosymmetric polymorph; hydrogen bonding; pharmaceuticals.

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[ doi:10.1107/S2053229614002447/sk3526Isup3.cml ]
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