Ammonium dichromate being lit
| IUPAC name
| Other names
|Molar mass||252.07 g/mol|
|Appearance||Orange crystalline solid|
|Melting point||180 °C (356 °F; 453 K) (decomposition)|
| 18.2 g/100ml (0 °C)|
35.6 g/100ml (20 °C)
40 g/100ml (25 °C)
156 g/100ml (100 °C)
|Solubility|| Soluble in alcohols|
Insoluble in acetone
|Safety data sheet||Sigma-Aldrich|
| Potassium dichromate|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Ammonium dichromate is the inorganic compound with the formula (NH4)2Cr2O7.
Ammonium dichromate decomposes when heated, releasing nitrogen, water vapors and green chromium(III) oxide particles in a manner similar to a volcanic eruption, hence why this property makes it widely used in various pyrotechnic demonstrations.
- (NH4)2Cr2O7 → Cr2O3 + N2 + 4 H2O
Ammonium dichromate is a red-orange solid, soluble in water and alcohols, but less so in other solvents.
Ammonium dichromate can be bought from various chemical suppliers. It can also be found on eBay and Amazon.
Since September 2017, ammonium dichromate is banned in EU.
Ammonium dichromate can be made by reacting sodium dichromate (which in turn can be made by the action of sodium hypochlorite aka household bleach to chromium(III) hydroxide or oxide) with ammonium chloride. Since sodium chloride is more soluble than ammonium dichromate at low temperatures, cooling the solution will cause ammonium dichromate to crystalize out of the solution.
Ammonium dichromate is flammable, oxidizer and a known carcinogen
Ammonium dichromate should be kept in plastic containers, with a proper label and a hazard symbol. Keep it away from acids and open flame sources.
Burning ammonium dichromate is not recommended, as small amounts of it will be spread in air.