We wish to investigate the origin of the promising thermoelectic performance of oxy-chalcogenides BiOCuQ (Q = S, Se, Te) and related phases. We wish to explore whether the low thermal conductivity of these materials at elevated temperatures is related to increasing levels of disorder of copper ions within a PbO-type [Cu2Q2]2- layer. We seek to collect powder neutron diffraction data on the stoichiometric phases in the temperature range 298