Title: Sodium Sulfide
CAS Registry Number: 1313-82-2
Additional Names: Sodium monosulfide; sodium sulfuret
Molecular Formula: Na2S
Molecular Weight: 78.04
Percent Composition: Na 58.92%, S 41.09%
Literature References: Best prepd from the elements in liq ammonia, also obtained by dehydration of the nonahydrate: Courtois, Compt. Rend. 207, 1220 (1938); Klemm et al., Z. Anorg. Allg. Chem. 241, 281 (1939); Feher in Handbook of Preparative Inorganic Chemistry vol 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 358-360. Review: C. Drum in Kirk-Othmer Encyclopedia of Chemical Technology vol. 21 (Wiley-Interscience, New York, 3rd ed., 1983) pp 256-262.
Properties: Cubic crystals or granules. Extremely hygroscopic. Discolors upon exposure to air. d414 1.856. mp 1180° (in vacuo); also reported as mp 920°. Soly in water (g/100 g H2O): 8.1 (-9.0°); 12.4 (0°); 18.6 (20°); 29.0 (40°); 35.7 (48°); 39.0 (50°). Slightly sol in alcohol. Insol in ether. Aq solns are strongly alkaline.
Melting point: mp 1180° (in vacuo); mp 920°
Density: d414 1.856
Derivative Type: Pentahydrate
Properties: Flat, shiny, four-sided, prismatic crystals. Loses 3 mols water at 100°. mp 120° (with loss of all water of crystn). Freely sol in water. Also sol in alcohol. Aq solns are strongly alkaline. Insol in ether. Dec by acids with evolution of H2S.
Melting point: mp 120° (with loss of all water of crystn)
Derivative Type: Nonahydrate
Properties: Tetragonal, deliquescent crystals. Odor of hydrogen sulfide. Discolors upon exposure to light and air (first yellow, then brownish-black). d416 1.427. mp ~50°. One gram dissolves in 0.5 ml water, also reported as 18 g dissolve in 100 ml water at 25°. Slightly sol in alcohol, insol in ether. Dec by acids, even by carbonic acid. Aqueous solns are very alkaline and upon standing in contact with air are slowly converted according to the equation: 2Na2S + 2O2 + H2O ® Na2S2O3 + 2NaOH. Exposure of the crystals to air produces hydrogen sulfide according to the equation Na2S + H2O + CO2 ® Na2CO3 + H2S. Keep well closed and in a cool place. Do not handle with bare hands.
Melting point: mp ~50°
Density: d416 1.427
Use: In dehairing hides and wool pulling; desulfurizing viscose rayon; in the manuf of rubber, sulfur dyes; in ore flotation, metal refining, engraving, cotton printing, as chemical intermediate, as laboratory reagent; in paper-pulping process. |