The Synthesis of Sodium Sulfide Pentahydrate, Na2S·5H2O, Through a Solid-Gas Reaction of Sulfidizing Gas Mixture with Sodium Carbonate, Na2CO3

Abstract

In this study, the sulfidization of Na2CO3 was investigated by using a solid-gas reaction under a sulfidizing gas mixture, which consisted of COS, CS2, and S2 gases. Sodium sulfide pentahydrate, Na2S·5H2O, was prepared from sodium carbonate, Na2CO3, via a sulfidizing gas mixture by a solid-gas reaction under the cooling of a nitrogen atmosphere. The observed phase was found to be the pentahydrated form of sodium sulfide. This crystalline form was determined by X-ray powder diffraction (XRD) technique. Since sodium sulfide is strongly hygroscopic, the pentahydrated crystalline form was observed in XRD measurements for all repeated experiments. The crystal unit cell parameters of the synthesized product were in excellent agreement with values given in the JCPDS card number 18-1249. The sodium sulfide pentahydrate has an orthorhombic crystal structure with the unit cell parameters of a = 6.475, b = 12.55, C = 8.655 Å, space group, Cmcm and Z = 4.