title: The structural properties of a noncentrosymmetric polymorph of 4-aminobenzoic acid.
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.
authors.affiliation: Laboratoire des Structures, Propriétés et Interactions Interatomiques, Université Abbes Laghrour-Khenchela, 40000 Khenchela, Algeria.
authors.forename: Rim
authors.initials: R
authors.lastname: Benali-Cherif
authors.affiliation: Laboratoire des Structures, Propriétés et Interactions Interatomiques, Université Abbes Laghrour-Khenchela, 40000 Khenchela, Algeria.
authors.forename: Radhwane
authors.initials: R
authors.lastname: Takouachet
authors.affiliation: Laboratoire de Cristallographie, Résonance Magnétique et Modélisations (CRM2, UMR CNRS 7036), Institut Jean Barriol, Université de Lorraine, BP 70239, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès Nancy, France.
authors.forename: El Eulmi
authors.initials: el E
authors.lastname: Bendeif
authors.affiliation: Laboratoire des Structures, Propriétés et Interactions Interatomiques, Université Abbes Laghrour-Khenchela, 40000 Khenchela, Algeria.
authors.forename: Nourredine
authors.initials: N
authors.lastname: Benali-Cherif
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry*; D003460:Crystallization; D006860:Hydrogen Bonding; D015394:Molecular Structure
chemical_list: D010129:4-Aminobenzoic Acid
keywords: 4-aminobenzoic acid; PABA; crystal structure; hydrogen bonding; noncentrosymmetric polymorph; pharmaceuticals; polymorphism