Potassium dichromate (K₂Cr₂O₇), commonly known as potassium bichromate or red vitriol potassium, is an orange-red triclinic or needle-like crystal with a melting point of 398°C and a boiling point of 500°C (decomposition). It is soluble in water, forming an acidic, corrosive, toxic, and strongly oxidizing solution.
Sodium dichromate (Na₂Cr₂O₇·2H₂O), commonly known as sodium bichromate or red vitriol sodium, is a red monoclinic prismatic or needle-like crystal with a melting point of 320°C and a boiling point of 600°C (decomposition). It loses its crystal water at 100°C to form the anhydrous form. The anhydrous form has a melting point of 356.7°C and decomposes at 400°C to release oxygen. It is highly hygroscopic and very soluble in water, forming a corrosive, toxic, and acidic solution with strong oxidizing properties.
