Potassium Dichromate (K₂Cr₂O₇)
Commonly known as potassium bichromate or red prussiate of potash. It appears as orange-red triclinic or needle-shaped crystals, with a melting point of 398°C and a boiling point of 500°C (decomposes upon boiling). It is soluble in water, forming an acidic solution with corrosive, toxic, and strong oxidizing properties.
Sodium Dichromate (Na₂Cr₂O₇·2H₂O)
Commonly known as sodium bichromate or red prussiate of soda. It occurs as red monoclinic prismatic or needle-shaped crystals, with a melting point of 320°C and a boiling point of 600°C (decomposes upon boiling). At 100°C, it loses crystal water to form the anhydrous form (Na₂Cr₂O₇), which has a melting point of 356.7°C and decomposes at 400°C while releasing oxygen. Sodium dichromate is highly hygroscopic, readily soluble in water, and its aqueous solution is acidic, corrosive, toxic, and exhibits strong oxidizing properties.
Key Notes:
Both compounds are carcinogenic and require strict safety handling due to their toxicity and environmental hazards.
Their strong oxidizing nature makes them hazardous when in contact with reducible substances or organic materials.
Waste disposal and environmental regulations must be strictly followed to prevent heavy metal pollution.
