Thermoelectric devices enable the conversion of thermal energy into electrical power. The development of new materials is essential to enable large scale implementation of thermoelectric technology. Argyrodites are attractive candidates due to their remarkably low thermal conduction. The argyrodite Cu8GeSe6 is a particularly attractive thermoelectric material, as chemical substitution can result in a figure of merit above unity. This proposal seeks to investigate the structure of Cu8GeSe6 as a function of temperature, in order to gain a better understanding of the features that lead to low thermal conduction.