title: Ammonium violurate: a compact structure with extensive hydrogen bonding in three dimensions.
abstract: The title compound [systematic name: ammonium pyrimidine-2,4-5,6(1H,3H)-tetrone 5-oximate], NH(4)(+).C(4)H(2)N(3)O(4)(-), crystallizes from water in the triclinic space group P\overline{1} and is ismorphous with a known rubidium complex [Gillier (1965). Bull. Soc. Chim. Fr. pp. 2373-2384]. The principal feature of the structure is hydrogen bonding; each ammonium H atom acts as a bifurcated donor and three of the four violurate O atoms are bifurcated acceptors, with the fourth acting as a trifurcated acceptor. The pattern of hydrogen bonding around the cation is very similar to the rubidium coordination environment in the related structure. The violurate anions pack as hydrogen-bonded crinkled tapes, which are linked and separated by the ammonium cations to give a compact three-dimensional structure.
authors.affiliation: School of Natural Sciences (Chemistry), Bedson Building, Newcastle University, Newcastle upon Tyne NE1 7RU, England. gsnichol@email.arizona.edu
authors.forename: Gary S
authors.initials: GS
authors.lastname: Nichol
authors.forename: William
authors.initials: W
authors.lastname: Clegg