The Direct Synthesis of Sodiun Polysulfides from Sodium and Sulfur

A method is described for synthesizing sodium polysulfides of stoichiometries Na2S3, Na2S4, and Na2S5 by the direct reaction of sodium and sulfur. The reaction is carried out in the furnace well of an inert−atmosphere glove box and features the slow addition of sulfur to molten sodium at temperatures ranging from 100–150°C at the start of the reaction to about 300°C at the end. Batches of 150–200 g of polysulfide product can be prepared with yields approaching 100% and a high purity.