CRYSTAL-STRUCTURE OF [BI1/133 CLASS 2/3 CU2O16](SO4)6

The aim of the present investigation has been to study how copper(II) is included in a bismuth oxide moeity. The title compound was synthesized and its crystal structure solved. The green crystals are orthorhombic with a = 20.550(3), b = 5.4364(11) and c = 7.4851(11) angstrom. The space group is Pmmn and Z = 1. R is 0.040 for the 875 reflections of the best data set registered. The main result is that copper(II) is included in a square endless Me2O2 layer which though pleated is similar to the Pb2F2(2+) layers in PbFCl and thus also to the Bi2O2(2+) layers in many bismuth oxide compounds. Similar pleated Me2O2 layers exist also in the previously known structure of [Bi2CoO3]SO4. The Cu atoms of the present structure are coordinated to four oxo oxygen atoms at 1.95(1) angstrom and are situated 0.34(1) angstrom outside the square plane of the O atoms. The next nearest Cu-O distance is 2.87(3) angstrom to a sulphate oxygen atom. The SO4 groups of the present compound are disordered in contrast to those of [Bi2CoO3]SO4. Some positions of the sulphate oxygen atoms given here are only tentative.