Copper(II) phosphate

Freshly ground copper(II) phosphate intended for use in blue paint

Copper(II) phosphate, or cupric phosphate, is a chemical compound with the formula Cu₃(PO₄)₂. It is a light blue powdery compound that is insoluble in water.

Properties

Chemical

Copper(II) phosphate will react with strong acids acids, such as sulfuric acid to produce the corresponding copper salt and phosphoric acid.

Physical

Copper(II) phosphate is a light blue, powdery substance that is insoluble in water and ethanol, but soluble in ammonia and mineral acids.

Availability

Copper(II) phosphate is usually unavailable for sale as it has very few applications. It is however extremely easy to prepare with OTC chemicals.

Preparation

Freshly precipitated and filtered copper(II) phosphate

Copper(II) phosphate can be prepared by combining copper(II) sulfate and trisodium phosphate in a 3:2 molar ratio.

3 CuSO_{4 (aq)} + 2 Na₃PO_{4 (aq)} → 2 Cu₃(PO₄)_{2 (s)} + 3 Na₂SO_{4 (aq)}

A different preparation involves reacting copper carbonate with phosphoric acid:

3 Cu₂CO₃(OH)₂ + 4 H₃PO₄ → 2 Cu₃(PO₄)₂ + 3 CO₂ + 9 H₂O

Monoammonium phosphate also works for this preparation.

Projects

• Copper compounds collection
• Paint pigments
• Copper (II) phosphate can be reduced to copper phosphide, which can be used to isolate elemental phosphorous by heating it: 4 Cu₃P₂ → 4 Cu₃P + P₄

Handling

Safety

Like all copper compounds, copper(II) phosphate is mildly toxic, but since it is insoluble it is less of a concern than soluble compounds.

Storage

Copper(II) phosphate should be stored in closed bottles.

Disposal

Copper phosphate should be disposed just like any other copper compound.

References

Relevant Sciencemadness threads

• Copper phosphate synthesis useing phosphoric acid???