The system NaNbO3 ¿ KNbO3 is one of the most widely studied as a ¿green¿ replacement for the piezoelectric material PZT (PbZr1-xTixO3). Despite its enormously growing significance over the last 4 years, the basic structural chemistry of this system is very poorly understood, with most of the crystallographic studies dating back to the 70s. The aim of this proposal is to study in detail both the end-member NaNbO3 and the solid-solution, at ambient temperature using high-resolution Xray powder diffraction. Specifically, we shall study samples prepared by a variety of means, both high-temperature solid state routes and softer sol-gel precursor routes. Careful and detailed analysis of these data by Rietveld analysis will be complemented by multinuclear solid state NMR and electrical measurements, in order to provide a comprehensive understanding of this technologically important system.