Crystal structures of copper(II) sodium carbonate trihydrate (chalconatronite)

Abstract

The crystal structure of the title compound has been determined from single-crystal photographic X-ray diffraction data by heavy-atom methods, and refined to R 0·13 for 995 visually estimated reflections. Crystals are monoclinic, space group P2₁/n, a= 13·81 (2), b= 6·10(1), c= 9·70(1)Å, β= 91·7(2)°, Z= 4.

The copper atom is co-ordinated in a distorted square pyramidal configuration by a water molecule at the apex [Cu-O 2·38(1)Å], a bidentate carbonate group [Cu–O,O′, 1·92, 1·97(1)Å], and a pair of crystallographically equivalent bridging carbonate groups [Cu–O,O′, 1·99, 1·98(1)Å] generating infinite anionic chains parallel to b about the crystallographic screw axes. The other two water molecules occupy lattice sites.