title: Poly[μ-aqua-diaquabis-[μ-2-cyano-2-(oxidoimino)-acetato]-copper(II)dipotassium].
abstract: In the title compound, [CuK(2)(C(3)N(2)O(3))(2)(H(2)O)(3)](n), the Cu(2+) atom is in a distorted square-pyramidal coordination geometry. Two N atoms belonging to the oxime groups and two O atoms belonging to the carboxyl-ate groups of two trans-disposed doubly deprotonated residues of 2-cyano-2-(hy-droxy-imino)-acetic acid make up the basal plane and the apical position is occupied by the water mol-ecule. The neighboring Cu-containing moieties are linked into a three-dimensional framework by K-O and K-N contacts formed by two potassium cations with the carboxyl-ate and the oxime O atoms and the nitrile N atoms of the ligand. The environments of the K(+) cations are complemented to octa- and nona-coordinated, by K-O contacts with H(2)O mol-ecules. The crystal structure features O-H⋯O hydrogen bonds.
authors.affiliation: Kiev National Taras Shevchenko University, Department of Chemistry, Volodymyrska Str. 64, 01601 Kiev,  Ukraine.
authors.forename: Irina A
authors.initials: IA
authors.lastname: Golenya
authors.forename: Yulia A
authors.initials: YA
authors.lastname: Izotova
authors.forename: Natalia I
authors.initials: NI
authors.lastname: Usenko
authors.forename: Valentina A
authors.initials: VA
authors.lastname: Kalibabchuk
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Kotova