title: Diaqua-bis-(2-oxo-2H-chromene-3-carboxyl-ato)copper(II).
abstract: In the title compound, [Cu(C(10)H(5)O(4))(2)(H(2)O)(2)], the Cu(II) atom lies on a crystallographic inversion center and exhibits an octa-hedral coordination defined by two O atoms from water mol-ecules in the axial positions and by four O atoms from two deprotonated coumarin-3-carb-oxy-lic acid ligands in the equatorial positions. The angles around the Cu(II) atom vary between 85.32 (6) and 94.68 (6)°. The Cu-O bond distances between the Cu(II) atom and the O atoms vary between 1.9424 (14) and 2.3229 (15) Å. The layers inter-digitate via face-to-face aromatic inter-actions [3.6490 (8) Å] between coumarin moieties such that the inter-layer separation is 10.460 (2) Å, i.e. the length of the c axis. O-H⋯O hydrogen bonds between the H atoms of coordinated water mol-ecules and the O atoms of carboxyl-ate groups link the complex mol-ecules into layers parallel to the ab plane.
authors.affiliation: College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Cui
authors.forename: Qian
authors.initials: Q
authors.lastname: Gao
authors.forename: Huan-Huan
authors.initials: HH
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Ya-Bo
authors.initials: YB
authors.lastname: Xie