The aims of the present proposal are twofold. Firstly to use very high resolution neutron diffraction data to establish accurate and precise structures of the novel piezoelectric material AgNbO3 from 10 K to 1000 K. Secondly to determine the structures formed in the solid solutions Ag1-xLixNbO3 x < 0.1 and for select examples investigate their temperature dependence. These two aims will be achieved using variable temperature powder neutron diffraction data recorded on HRPD. Neutron diffraction is critical for this work since the structures of interest differ in the nature of the tilting of the oxygen octahedra and displacements of particular ions.