Indole-3-carboxylic acid

Abstract

The crystal structure of indole-3-carboxylic acid, C9H 7NO2, shows the presence of centrosymmetric hydrogen-bonded cyclic carboxylic acid dimers [O⋯O = 2.649 (2) Å]. These dimers are linked into a sheet structure through peripheral intermolecular hydrogen bonds between the carboxylic acid groups and the hetero-amine group of the n-glide-related indole ring [O⋯N = 3.013 (2) Å]. © 2003 International Union of Crystallography Printed in Great Britain - all rights reserved.