Sodium Sulfide

Core Chemical Properties

· Appearance: Pure anhydrous and hydrated forms are colorless solids. However, industrial or technical-grade versions are typically sold as yellow, pink, or brick-red flakes due to the presence of polysulfides.

· Molar Mass: 78.05 g/mol (anhydrous form).

· Odour: It possesses a distinct, highly unpleasant rotten egg smell. This occurs because the compound readily hydrolyzes upon contact with moist air, releasing toxic hydrogen sulfide gas (H₂S).

· Alkalinity: When dissolved in water, it creates a strongly basic (alkaline) solution with a pH well above 7, making it highly corrosive.

· Hydration: It most commonly exists in commerce as a nonahydrate form (Na₂S⋅9H₂O) or as technical-grade flakes containing roughly 60% Na₂S by weight.

�� Industrial Applications

Sodium sulfide serves a cornerstone role across several major manufacturing fields:

· Pulp and Paper Industry: It is an essential component of the Kraft process, where it helps dissolve and break down tough lignin in wood fibers to produce high-quality paper.

· Leather Processing: Used as a dehairing/unhairing agent to remove fur and hair from animal hides during the pre-tanning stage.

· Textile Manufacturing: Acts as a bleaching, dechlorinating, and desulfurizing agent, and plays an integral role in the formulation of sulfur dyes.

· Water Treatment: It acts as an oxygen scavenger and works as a precipitant to remove heavy metal contaminants from industrial wastewater.

· Chemical Synthesis: Employed as a reducing agent and in the synthesis of various rubber chemicals and polymers.

· Medical Gel: In low, controlled concentrations, it is formulated into topical over-the-counter gels designed to soften ingrown toenails, making them easier to trim and alleviating localized pain.