Sodium Hydrosulfide, Sodium Hydrogen Sulfide, Sodium Bisulfide, Sodium Sulfhydrate, Sodium Hydrosulphide Hydrated, Sodium Hydrosulphide Monohydrate, 207683-19-0, 140650-84-6

SODIUM HYDROSULFIDE (HYDRATED AND MONOHYDRATE)

Sodium Hydrosulfide / Sodium Hydrogen Sulfide / Sodium Bisulfide / Sodium Sulfhydrate
CAS Numbers: 207683-19-0 (Hydrated); 140650-84-6 (Monohydrate)

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

Sodium hydrosulfide is the sodium salt of hydrogen sulfide (H₂S). It is an inorganic compound with strong reducing properties that forms an alkaline solution when dissolved in water. The hydrated form (NaHS·xH₂O, x=2-3) is widely used in industrial applications, while the monohydrate form (NaHS·H₂O) is preferred for more controlled reactions and laboratory applications. Both forms are used in water and wastewater treatment for heavy metal precipitation, in the textile and paper industry as a bleaching and auxiliary chemical, and in the synthesis of organo-sulfur compounds as a reducing agent.

2. SYNONYMS AND OTHER NAMES

3. CHEMICAL STRUCTURE

3.1. Molecular Structure (Anhydrous Form)

Sodium hydrosulfide is the sodium salt of hydrogen sulfide (H₂S). The structure consists of a hydrosulfide anion (HS⁻) and a sodium cation (Na⁺). The HS⁻ ion has a linear structure consisting of a sulfur atom bonded to a hydrogen atom.

Simplified Structural Formula:

Na⁺  [ H - S ]⁻

More Detailed Representation:

Na⁺  S²⁻  H⁺
      |     |
NaHS → Na⁺ + HS⁻ (ionization in water)

3.2. Molecular Formula

3.3. Molecular Weight

3.4. Key Structural Features

4. PHYSICAL AND CHEMICAL PROPERTIES

5. SOLUBILITY PROFILE

6. CHEMICAL PROPERTIES AND REACTIVITY

7. REACTION EQUATIONS

7.1. Dissolution in Water (Ionization)

NaHS → Na⁺ + HS⁻

7.2. Hydrolysis (Alkaline Solution Formation)

HS⁻ + H₂O ⇌ H₂S + OH⁻

7.3. Reaction with Acids (H₂S Gas Release)

NaHS + HCl → NaCl + H₂S ↑

NaHS + H₂SO₄ → NaHSO₄ + H₂S ↑

7.4. Oxidation in Air (Sodium Thiosulfate Formation)

2NaHS + 2O₂ → Na₂S₂O₃ + H₂O

7.5. Heavy Metal Precipitation (Cu, Pb, Zn)

Cu²⁺ + HS⁻ → CuS↓ + H⁺

Pb²⁺ + HS⁻ → PbS↓ + H⁺

Zn²⁺ + HS⁻ → ZnS↓ + H⁺

7.6. Reaction with Strong Base

NaHS + NaOH → Na₂S + H₂O

8. HYDRATED AND MONOHYDRATE FORMS COMPARISON

9. PRODUCTION METHOD

Sodium hydrosulfide is produced by the reaction of hydrogen sulfide (H₂S) gas with sodium hydroxide (NaOH).

Reaction:

H₂S + NaOH → NaHS + H₂O

Production Stages:

10. APPLICATIONS AND INDUSTRIAL USES

10.1. Water and Wastewater Treatment (Most Important Application)

10.2. Textile and Paper Industry

10.3. Chemical Synthesis

10.4. Laboratory and Research (Monohydrate)

10.5. Other Applications

11. CHEMICAL COMPATIBILITY TABLE

12. TOXICOLOGICAL PROFILE

H₂S Gas Toxicity:

• H₂S is a colorless, toxic, flammable, and explosive gas.

• At low concentrations (10-50 ppm): respiratory irritation and headache.

• At moderate concentrations (100-200 ppm): olfactory paralysis (loss of smell).

• At high concentrations (>500 ppm): respiratory paralysis and death.

13. GHS CLASSIFICATION AND LABELING

GHS Classification:

Signal Word: DANGER

Hazard Pictograms: GHS06 (Skull and Crossbones), GHS05 (Corrosive), GHS09 (Environment)

Hazard Statements (H-Codes):

14. PRECAUTIONARY STATEMENTS (P-CODES)

15. FIRST AID MEASURES

16. FIRE-FIGHTING MEASURES

17. ACCIDENTAL RELEASE MEASURES

18. STORAGE AND SHELF LIFE

19. PACKAGING OPTIONS

20. TRANSPORT INFORMATION

21. REGULATORY STATUS

22. SECTORAL SUITABILITY TABLE

23. HYDRATED AND MONOHYDRATE COMPARISON TABLE

24. QUICK REFERENCE TABLE

25. CRITICAL NOTICES AND BEST PRACTICES

CRITICAL NOTICES:

1. H₂S Gas Hazard: Sodium hydrosulfide releases toxic and fatal hydrogen sulfide (H₂S) gas upon contact with acids. H₂S can cause respiratory paralysis and death. Avoid all contact with acids.

2. Olfactory Paralysis: H₂S has a rotten egg odor at low concentrations, but at high concentrations it paralyzes the sense of smell. Do not rely on odor; use gas detectors.

3. Corrosive Effect: Sodium hydrosulfide solutions are alkaline and can cause severe burns to skin, eyes, and mucous membranes. Use protective equipment.

4. Air and Moisture Sensitivity: The product oxidizes in air and absorbs moisture. Must be stored under inert atmosphere (nitrogen).

5. Fire and Explosion: The solid form (monohydrate) is classified as spontaneously combustible (UN 2949, Class 4.2). Contact with oxidizers may cause fire.

6. Environmental Impact: Very toxic to aquatic organisms (H400). Avoid release to the environment.

7. UN Number Difference: Hydrated form is UN 2948 (Class 8, Corrosive), while monohydrate is UN 2949 (Class 4.2, Spontaneously Combustible). This difference must be considered in transport and storage.

BEST PRACTICE RECOMMENDATIONS:

• Storage: Store in a cool, dry, and well-ventilated area under inert atmosphere (nitrogen), in tightly closed containers. Keep away from acids, oxidizers, and moisture.

• Personnel Protection: Use full protective clothing, self-contained breathing apparatus (SCBA), chemical-resistant gloves, and goggles. Ensure adequate ventilation.

• Dosage Control: Determine the correct dosage for water treatment and chemical synthesis. Overdosing may cause H₂S release.

• Solution Preparation: Always prepare solutions in cold water. Avoid acid addition at all times.

• Waste Management: Dispose of unused product and waste at licensed facilities. Do not pour down drains.

• H₂S Monitoring: Use continuous H₂S gas detectors in work areas.

• Emergency Plan: Prepare emergency plans and first aid procedures for H₂S leaks or exposure.

LEGAL DISCLAIMER:

The information provided in this document is based on our current knowledge and experience and is presented in good faith; however, as all conditions of use are beyond our control, it does not constitute a binding specification or warranty. This Technical Data Sheet is for informational purposes only. Users are obligated to test the suitability of the product for their own applications. For complete safety, storage, handling, transport, waste, and regulatory compliance information, the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier must be consulted.