We wish to collect powder neutron diffraction as a function of temperature on four samples of argyrodites, A8GeQ6 (A = Cu, Ag; Q = S, Se), to investigate structural phase transitions, cation ordering and cation mobility. The structure at room temperature consists of tetrahedral GeQ4 units which link AQ4 units into an open structure that contains additional 3-coordinate A cations. Structural transitions are reported to occur in the temperature range 320 < T/K < 500. We seek to investigate the onset of copper (silver) ion mobility at the phase transition and its evolution with temperature. We believe these materials to be examples of phonon-liquid-electron-crystals, which emerging evidence suggests is linked to exceptionally low thermal conductivity and thus high thermoelectric performance.