title: A polymorph of diaqua-bis(pyrazine-2-carboxyl-ato-κN,O)copper(II).
abstract: The title compound, [Cu(C(5)H(3)N(2)O(2))(2)(H(2)O)(2)], is a new polymorph of the previously reported compound [Klein et al. (1982 ▶). Inorg. Chem.21, 1891-1897]. The Cu(II) atom, lying on an inversion center, is coordinated by two N atoms and two O atoms from two pyrazine-2-carboxyl-ate ligands and by two water mol-ecules in a distorted octa-hedral geometry with the water mol-ecules occupying the axial sites. Inter-molecular O-H⋯O, O-H⋯N and C-H⋯O hydrogen bonds connect the complex mol-ecules into a two-dimensional layer parallel to (10), whereas the previously reported polymorph exhibits a three-dimensional hydrogen-bonded network.
authors.affiliation: The State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
authors.forename: Guan-Hua
authors.initials: GH
authors.lastname: Wang
authors.forename: Ren-Ling
authors.initials: RL
authors.lastname: He
authors.forename: Fan-Jin
authors.initials: FJ
authors.lastname: Meng
authors.forename: Ning-Hai
authors.initials: NH
authors.lastname: Hu
authors.forename: Jing-Wei
authors.initials: JW
authors.lastname: Xu