title: Disodium tricopper(II) tetra-kis[selenate(IV)] tetra-hydrate.
abstract: The title compound, Na(2)Cu(3)(SeO(3))(4)(H(2)O)(4), has been prepared under hydro-thermal conditions. The crystal structure contains a three-dimensional anionic framework made up from distorted [CuO(4)(H(2)O)(2)] octa-hedra ( symmetry), [CuO(4)(H(2)O)] square pyramids and trigonal-pyramidal SeO(3) units sharing common corners. The connectivity among these units leads to four- and eight-membered polyhedral rings, which by edge-sharing inter-connect into walls. A rhombus-like 16-membered polyhedral ring channel system with a longest length of approximately 14.0 Å and a shortest length of 5.3 Å is enclosed by such walls along the a axis. The water mol-ecules attached to the Cu atoms, as well as the electron lone pairs of the Se(IV) atoms, protrude into these channels. The seven-coordinated Na(+) counter-cations occupy the remaining free space of the 16-membered polyhedral ring channels. An intricate network of O-H⋯O hydrogen bonds further consolidates the three-dimensional structure.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Kai
authors.initials: K
authors.lastname: Hu
authors.forename: Lixin
authors.initials: L
authors.lastname: Cao
authors.forename: Ge
authors.initials: G
authors.lastname: Su
authors.forename: Jingtai
authors.initials: J
authors.lastname: Zhao