Sodium sulfide

Sodium sulfide

Names
IUPAC name Sodium sulfide
Other names Disodium sulfide Disodium monosulfide
Identifiers
Jmol-3D images	Image
SMILES [Na+].[Na+].[S-2]
Properties
Chemical formula	Na2S
Molar mass	78.0452 g/mol (anhydrous) 240.18 g/mol (nonahydrate)
Appearance	Colorless hygroscopic solid
Odor	Rotten eggs
Density	1.856 g/cm3 (anhydrous) 1.58 g/cm3 (pentahydrate) 1.43 g/cm3 (nonohydrate)
Melting point	1,176 °C (2,149 °F; 1,449 K) (anhydrous) 100 °C (212 °F; 373 K) (pentahydrate) 50 °C (122 °F; 323 K) (nonahydrate)
Boiling point	Decomposes
Solubility in water	12.4 g/100 ml (0 °C) 18.6 g/100 ml (20 °C) 39 g/100 ml (50 °C) Hydrolysis
Solubility	Slightly soluble in alcohol Insoluble in diethyl ether
Hazards
Safety data sheet	Sigma-Aldrich Sigma-Aldrich (nonahydrate)
Related compounds
Related compounds	Hydrogen sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium sulfide is the chemical compound with the chemical formula Na₂S, or more commonly its nonahydrate form Na₂S·9H₂O.

Properties

Chemical

Sodium sulfide reacts with acids to release hydrogen sulfide.

Na₂S + 2 HX → H₂S + 2 NaX

Physical

Sodium sulfide is a white solid, though impure samples can be yellow or reddish. It has an unpleasant odor of rotten eggs, from the hydrogen sulfide released by the hydrolysis in moist air.

Availability

Sodium sulfide is sold by chemical suppliers, though it's not easy to get a hold of in most places.

Preparation

Industrially Na₂S is produced by carbothermic reduction of sodium sulfate often using coal:

Na₂SO₄ + 2 C → Na₂S + 2 CO₂

In the laboratory, this compound salt can be prepared by reacting elemental sulfur with sodium in anhydrous ammonia, in dry THF with a catalytic amount of naphthalene (forming sodium naphthalenide):

2 Na + S → Na₂S

Projects

• Make hydrogen sulfide (DANGEROUS)
• Make thioethers
• Precipitate mercury ions

Handling

Safety

Like sodium hydroxide, sodium sulfide is strongly alkaline and can cause skin burns. Acids react with it to rapidly produce hydrogen sulfide, which is highly toxic.

Storage

In closed and air-tight bottles, away from moisture and acids.

Disposal

Sodium sulfide can be neutralized with bleach or hydrogen peroxide.

References

Relevant Sciencemadness threads

• Sodium sulfide production
• Preparation of sodium sulfite (and other sulfites as well)
• Sodium sulfide and aluminium metal reaction
• Sodium sulphide