title: A new polymorph of 5-nitro-uracil monohydrate.
abstract: In the title compound, C(4)H(3)N(3)O(4)·H(2)O, mol-ecules of 5-nitro--uracil are hydrogen bonded in pairs across crystallographic centers of symmetry. The resulting dimers are also hydrogen bonded to the water mol-ecules, forming a three-dimensional network. The pyrimidine ring is almost planar (with a maximum deviation of 0.0156 (9) Å for the one of the N atoms) and the nitro group is rotated by 12.4 (1)° out of the uracil plane, while in the other polymorph the value for the same angle is 5°.
authors.affiliation: CEMDRX, Physics Department, University of Coimbra, P-3004-516 Coimbra, Portugal.
authors.forename: P S
authors.initials: PS
authors.lastname: Pereira Silva
authors.forename: S R
authors.initials: SR
authors.lastname: Domingos
authors.forename: M
authors.initials: M
authors.lastname: Ramos Silva
authors.forename: J A
authors.initials: JA
authors.lastname: Paixão
authors.forename: A
authors.initials: A
authors.lastname: Matos Beja