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<T/K<673, to investigate the evolution with temperature of the detailed structure of the Cu2Q2 layer. We also aim to collect data on the first members of a series in which there is partial replacement of trivalent bismuth with divalent lead to investigate the structural impact of the oxidation of copper that results from substitution. We will also collect reference data on Cu2-xSe which has recently been shown to exhibit a high TE figure of merit.