Sodium Dichromate Extra Pure

1. Basic Identification Attributes

• Chemical Name: Sodium Dichromate
  • CAS Number: 10588-01-9 (dihydrate), 7789-12-0 (anhydrous)
  • HS Code: 2841.30.00
  • Molecular Formula: Na₂Cr₂O₇·2H₂O (for dihydrate)
  • Synonyms:

• Disodium dichromate
• Sodium bichromate
• Dichromic acid, disodium salt
• Chromic acid disodium salt

2. Physical & Chemical Properties

Physical State: Solid (crystalline or granular)
• Color & Odor: Bright orange to reddish-orange, odorless
• Melting Point: 356 °C (anhydrous, decomposes)
• Density/Specific Gravity: ~2.52 g/cm³ (dihydrate)
• Solubility:

• Highly soluble in water (~73 g/100 mL at 20 °C)
• Insoluble in alcohol and organic solvents
  • pH Level: Acidic (~4.0 in 1% aqueous solution)
  • Oxidizing Properties: Strong oxidizer
  • Vapor Pressure & Volatility: Negligible volatility
  • Flash Point: Not flammable

3. Safety & Hazard Attributes

Hazard Class (GHS Classification):

• Carcinogenicity (Category 1B)
• Acute toxicity – oral/inhalation (Category 3)
• Skin corrosion (Category 1B)
• Eye damage (Category 1)
• Germ cell mutagenicity (Category 1B)
• Respiratory sensitization (Category 1)
• Aquatic toxicity – acute and chronic (Category 1)
  • NFPA Ratings:
• Health: 4
• Flammability: 0
• Reactivity: 1
  • Exposure Limits:
• OSHA PEL: 0.005 mg/m³ (as Cr(VI))
• ACGIH TLV: 0.05 mg/m³ (as Cr(VI), TWA)
  • Reactivity:
• Reactive with organic materials, reducing agents, and acids
• Releases toxic chromium fumes when heated

4. Storage & Handling Attributes

Storage Conditions:

• Store in a tightly sealed container in a cool, dry, well-ventilated area
• Avoid exposure to direct sunlight, heat, or moisture
  • Incompatible Materials:
• Organic substances, reducing agents, acids, ammonium salts
  • Container Type:
• Corrosion-resistant or plastic-lined containers
  • Shelf Life & Expiration Date:
• Stable if kept dry and uncontaminated
  • Special Handling Requirements:
• Use only with appropriate PPE
• Avoid generating dust
• Handle under fume hood in controlled environments

5. Regulatory & Compliance Attributes

Regulatory Status:

• Strictly regulated due to hexavalent chromium content
• Listed under REACH SVHC and U.S. EPA hazardous substances
• Subject to OSHA Hexavalent Chromium Standards (29 CFR 1910.1026)
  • Transportation Restrictions:
• Regulated as a hazardous material (UN 3288 – Toxic Solid, Inorganic, N.O.S.)
  • Waste Disposal Method:
• Dispose through licensed hazardous waste disposal services
• Must not be disposed of in general wastewater systems

6. Environmental & Health Impact

Ecotoxicity:

• Highly toxic to aquatic organisms
• Persistent in aquatic and soil environments
  • Persistence in Environment:
• Cr(VI) compounds do not degrade readily and pose long-term environmental risk
  • Carcinogenicity/Mutagenicity:
• Classified as a known human carcinogen by IARC, NTP, and OSHA
• Capable of causing genetic mutations and reproductive toxicity
  • Biodegradability:
• Inorganic and not biodegradable
• Requires chemical reduction to less toxic Cr(III) form before disposal