Preparation of sodium sulfide
Hydrogen sulfide is passed through 3 parts of concentrated sodium hydroxide solution until no further absorption takes place. Then 2 parts of concentrated sodium hydroxide solution is added in order to neutralize sodium hydrosulfide. The rule, however, is to add only two-thirds of the quantity of the solution of sodium hydroxide, as it is better the preparation should contain a little sodium hydrosulfide than that free sodium hydroxide should be present. Sodium sulfide should be well protected from air and moisture.
Laboratory manual of inorganic preparations, by H. T. Vulte, 43, 1895
Preparation of anhydrous sodium sulfide
The sodium sulfide nonahydrate, Na2S · 9H2O, is heated in a distilling flask or a retort in a stream of hydrogen or of nitrogen until water ceases to be evolved. The solid cake of anhydrous sodium sulfide is removed from the vessel and stored in a well-stoppered container protected from atmosphere moisture. No attempt should be made to fuse the sodium sulfide in an air since at high temperatures sodium sulfide is readily oxidized by the oxygen to sodium sulfate.
A text book of practical organic chemistry, by A. I. Vogel, 197, 1974
Sodium sulfide (Na2S), Sodium monosulfide, Disodium monosulfide, Disodium sulphide, Sodium sulfide hydrate, Sodium sulfide (VAN), Sodium sulfide (anhydrous), HSDB 772, Sodium sulfide, anhydrous (DOT), AI3-09342, Sodum sulfuret, Na2-S, Sodium sulfide, anhydrous, Disodium sulfide (Na2S), 13468_RIEDEL, 407410_ALDRICH, 71975_FLUKA, MolPort-001-783-714, 13468_SIAL, NSC41874, NSC-41874, Sodium sulfide (Na2S) (8CI,9CI), AB1002292, FT-0083156, Sodium sulfide, hydrated with at least 30% water, I14-43450, I14-44279, Sodium sulfide, hydrated with at least 30% water [UN1849] [Corrosive], Sodium sulfide, anhydrous or sodium sulfide with <30% water of crystallization, 113584-74-0, Sodium sulfide, anhydrous or sodium sulfide with <30% water of crystallization [UN1385] [Spontaneously combustible]
SODIUM SULFIDE, Disodium sulfide, Sodium sulphide, null, Sodium sulfuret, Na2S, Sodium sulfide solution, UNII-YGR27ZW0Y7, EINECS 215-211-5, CID237873, NSC 41874, UN1385, UN1849, Sodium sulfide solution (15% or less), Sodium sulfide solution (25% or less), 1313-82-2, 27610-45-3