title: N,N'-Di-hydroxy-benzene-1,2:4,5-tetra-carboximide dihydrate.
abstract: In the title compound, C10H4N2O6·2H2O, the organic mol-ecule has crystallographically imposed inversion symmetry. The atoms of the three fused rings of the mol-ecule are coplanar within 0.0246 (8) Å, while the two hy-droxy O atoms are displaced from the mean plane of the mol-ecule by 0.127 (1) Å. In the crystal, infinite near-planar layers of close-packed mol-ecules are formed by hydrogen bonding between water O-H donor groups and carbonyl O-atom acceptors, and by weak inter-actions between C-H donor groups and water O-atom acceptors. The layers are parallel to the {102} family of planes. The stacked planes are held together by hydrogen bonding between N-OH donor groups and water O-atom acceptors.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Napoli 'Federico II', Complesso di Monte S. Angelo, Via Cinthia, 80126 Napoli, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Centore
authors.forename: Antonio
authors.initials: A
authors.lastname: Carella
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Acta Crystallogr Sect E Struct Rep Online. 2013 Apr 05;69(Pt 5):o667-8
references.pmid: 23723829
references.citation: Acta Crystallogr Sect E Struct Rep Online. 2013 Apr 27;69(Pt 5):o802-3
references.pmid: 23723943