The rapid synthesis of alkali metal fullerides using a microwave-induced argon plasma (MIAP) is reported. Reaction times are of the order of seconds using a MIAP, whereas conventional synthesis requires times of the order of several days. Potassium, rubidium, and cesium fullerides are more readily synthesized by this technique than sodium fullerides. Investigation of sodium fulleride synthesis via both conventional and microwave routes, combined with 13 C MAS NMR spectroscopy and powder X-ray Rietveld analysis, gives an improved understanding of the sodium-C 60 phase diagram.