We request 3 days’ beam time on POLARIS for in-situ powder diffraction studies of the reactions of lithium amide or lithium imide with manganese(IV) oxide under flowing argon or ammonia. This novel synthesis method has recently produced the new ternary lithium-manganese oxide, Li10Mn4O9. POLARIS is the beamline of choice to determine the nature of these materials as they are synthesised, since it has good resolution and also has an in-situ gas flow cell with bespoke shielding. The knowledge gained will be used to inform the direction of novel syntheses with the hope of generating new materials relevant for energy storage applications.