Sodium dichromate dihydrate (Na2Cr2O7•2H2O)-Crystalline

Characteristic

Sodium dichromate is the inorganic compound with the formula Na₂Cr₂O₇. Usually, however, the salt is handled as its dihydrate Na₂Cr₂O₇·2H₂O. 

Chemical formula：Na₂Cr₂O₇

Molar mass：261.97 g/mol (anhydrous)；298.00 g/mol (dihydrate)

Appearance：bright orange

Odor：odorless

Density：2.52 g/cm³

Melting point：356.7 °C (674.1 °F; 629.8 K)

Boiling point：400 °C (752 °F; 673 K) decomposes

Solubility in water：73 g/100 mL at 25 °C

Solubility in other solvents：soluble in methanol, ethanol

Refractive index (nD)：1.661 (dihydrate)

Application

Sodium dichromate is used as a strong oxidizing agent in organic synthesis. It is used in metal finishing as an aid of corrosion resistance, manufacture of inorganic chromate pigments and in the preparation of colored glass and ceramic glazes. It is used as a mordant for acidic dyes to improve their color-fast properties and as a corrosion inhibitor in undercoats and primers.