Ammonium chromate

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Ammonium chromate
Names
IUPAC name
Ammonium chromate
Other names
Ammonium chromate(IV)
Diammonium chromate
Diazanium dioxido(dioxo)chromium
Properties
(NH4)2CrO4
Molar mass 152.07 g/mol
Appearance Yellow crystalline solid
Odor Ammonia
Density 1.90 g/cm3
Melting point 185 °C (365 °F; 458 K) (decomposes)
Boiling point Decomposes
24.8 g/100ml (0 °C)
37.36 g/100ml (25 °C)
45.3 g/100ml (40 °C)
70.06 g/100ml (75 °C)
Solubility Sparingly soluble in acetone, liq. ammonia, methanol
Practically insoluble in ethanol
Thermochemistry
657 J·K-1·mol-1
-1,163 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Related compounds
Related compounds
Potassium chromate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium chromate is a salt with the formula (NH4)2CrO4.

Properties

Chemical

Ammonium chromate, like ammonium dichromate burns when ignited, creating a volcano-like effect.

Physical

Ammonium chromate is a yellow solid, soluble in water, sparingly soluble in organic solvents.

Availability

Can be purchased from chemical suppliers.

Preparation

Ammonium chromate can be made by mixing an equimolar quantities of ammonia and ammonium dichromate.

Another route involves mixing ammonium perchlorate with sodium chromate. Ammonium chromate is less soluble than NaClO4 and will precipitate out of the solution.

Projects

  • Make chromium(III) oxide

Handling

Safety

Ammonium chromate is flammable and extremely toxic. It is a known carcinogen. Wear proper protection, such as gloves and a mask.

Storage

Ammonium chromate should be stored in closed bottles, in well ventilated places. As it gives off ammonia over time, the bottle should be open periodically.

Disposal

Ammonium chromate can be neutralized with a reducing agent, such as ascorbic acid or sodium/potassium sulfite/metabisulfite/thiosulfate.

References

Relevant Sciencemadness threads