inorganic compounds
The title compound, tricopper erbium chloride bis(oxide) bis[trioxoselenate(2-)], consists of an infinite three-dimensional framework of cations and O atoms, and contains eight-coordinate Er3+, square-planar Cu2+, and three-coordinate Se4+ ions. The Cl ions and the Se lone pair of electrons occupy tunnels parallel to [001]. The mean bond distances are: Er-O 2.38 (8) Å, Cu1-O 1.96 (7) Å (in the square planes), Cu1-Cl 3.015 Å (out-of-plane), Cu2-O 1.95 (3) Å, Cu2-Cl 3.1753 Å and Se-O 1.696 Å. The shortest CuCu distance is 3.150 Å, and the shortest OO distance is 2.48 Å (O3O3).