5-Aminoisophthalic Acid Hemihydrate

Document Type

Article

Publication Date

1998

Publication Title

Acta Crystallographica Section C: Structural Chemistry

DOI

10.1107/S0108270198005915

ISSN

2053-2296

Abstract

The title acid, C8H7NO4.0.5H2O, crystallized in the centrosymmetric space group C2/c in a zwitterionic form (5-ammonioisophthalate), with the water molecule on a twofold axis. The three ammonio H atoms and the H atom on the remaining carboxyl group, which are involved in hydrogen bonding, are ordered. Three intermolecular N-HO hydrogen bonds have NO distances ranging from 2.762 (2) to 2.905 (2) Å and N-HO angles ranging from 155 (2) to 163 (2)°. Two intermolecular O-HO hydrogen bonds have OO distances of 2.536 (2) and 2.746 (2) Å, and O-HO angles of 178 (2) and 176 (2)°. A three-dimensional network of hydrogen bonds is present. Through basic second-level graphs involving acid-to-acid hydrogen bonds, chains are more numerous than rings.

Comments

Copyright, 1999, International Union of Crystallography

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