Potassium Dichromate
| Formula: | Cr2K2O7 |
| Chemical formula: | K2Cr2O7 |
| Density: | 2.69 g/cm3 (20°C) |
| Molar mass: | 294.19 g/mol |
| Bulk density: | 1250 kg/m3 |
| CAS number: | 7778-50-9 |
| EC index number: | 024-002-00-6 |
| HS code: | 28415000 |
| EC number: | 231-906-6 |
| Storage (temperature): | Without limitations. |
| SDS | available |
| R phrase: | R 45-46-60-61-8-E… |
| S phrase: | S 53-45-60-61 |
| Odour: | odourless |
| Form: | solid |
| Color: | orange |
| PH value: | 3.57 (100 g/l) |
| Solubility in water: | 130 g/l (20 °C) |
| Boiling point: | > 500 °C |
| Melting point: | 398 °C |
| Thermal decomposition: | ~ 500 °C |
| Assay | ≥ | 99/5 | % |
| Description | Conforms | ||
| Solubility | Conforms | ||
| Identification | Conforms | ||
| Sulfate | ≤ | 0/005 | % |
| Chloride | ≤ | 0/001 | % |
| Clarity & color of solution | Conforms | ||
| Loss on drying | ≤ | 0/5 | % |
Potassium dichromate is a bright orange-red crystalline inorganic compound that is widely used as a strong oxidizing agent in laboratories and industry. It contains hexavalent chromium and is known for its high reactivity and toxicity.
🏭⚗️ Production
Potassium dichromate is produced by roasting chromite ore with potassium carbonate in the presence of air to form potassium chromate, which is then acidified with sulfuric acid to yield potassium dichromate. The product is purified through crystallization.
🔬 Properties
Potassium dichromate has the chemical formula K₂Cr₂O₇ and a molar mass of approximately 294.18 g/mol. It appears as bright orange-red triclinic crystals that are soluble in water, forming an acidic solution. It is a powerful oxidizing agent and is stable under dry conditions. When heated or mixed with reducing agents, it can react vigorously or explosively.
🧪 Applications
Potassium dichromate is used in various analytical chemistry procedures, including redox titrations and the detection of alcohols. It is also employed in the preparation of photographic materials, as a wood preservative, in metal surface treatment, and in the synthesis of other chromium compounds. Historically, it was used in cleaning laboratory glassware and as a component in some inks and dyes.
⚠️ Safety
Potassium dichromate is highly toxic and a known carcinogen due to its hexavalent chromium content. It can cause severe irritation or burns to the skin, eyes, and respiratory tract, and long-term exposure can lead to cancer and organ damage. It should be handled only with proper protective equipment in well-ventilated areas, and all waste must be disposed of as hazardous material according to environmental regulations.
