Ammonium heptamolybdate

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Ammonium heptamolybdate
Ammonium heptamolybdate tetrahydrate sample.jpg
Ammonium heptamolybdate tetrahydrate
Names
IUPAC name
Ammonium docosaoxoheptamolybdate(6–)
Other names
Ammonium paramolybdate
Properties
(NH4)6Mo7O24 (anhydrous)
(NH4)6Mo7O24·4H2O (tetrahydrate)
Molar mass 1163.9 g/mol (anhydrous)
1235.86 g/mol (tetrahydrate)
Appearance White solid
Density 2.498 g/cm3
Melting point tetrahydrate
90 ˚C (194 ˚F; 363 K)
anhydrous
190 °C (374 ˚F; 463 K) (decomposition)
Boiling point Decomposes
tetrahydrate
43 g/100 ml
Hazards
Safety data sheet Sigma-Aldrich (tetrahydrate)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium heptamolybdate is an inorganic compound with the chemical formula (NH4)6Mo7O24. It is commonly encounteres as tetrahydrate (NH4)6Mo7O24·4H2O.

While it is also referred to as ammonium molybdate, the term is also used for ammonium orthomolybdate, (NH4)2MoO4.

Properties

Chemical

Ammonium heptamolybdate decomposes when heated.

Physical

Ammonium heptamolybdate is a white solid, soluble in water.

Availability

Can be purchased from chemical suppliers, or online from eBay.

Preparation

Ammonium heptamolybdate can be easily prepared by dissolving molybdenum trioxide in an excess of aqueous ammonia, followed by evaporating the solution at room temperature.

Projects

  • Phosphate detection
  • Make colorful solutions
  • Make potassium heptamolybdate

Handling

Safety

Ammonium heptamolybdate is irritant to touch and harmful if ingested.

Storage

In closed bottles, away from acidic vapors.

Disposal

Heating will cause it do decompose to MoO3.

References

Relevant Sciencemadness threads