Silver phosphate

Silver phosphate or silver orthophosphate is a light sensitive, yellow, water-insoluble chemical compound composed of silver and phosphate ions of formula Ag₃PO₄.

Silver phosphate is formed as a yellow solid precipitate by the reaction between a soluble silver salt, such as silver nitrate, with a soluble orthophosphate. Its solubility product is 8.89×10⁻¹⁷ mol⁴·dm⁻². The precipitation reaction is analytically significant and can be used in qualitative or quantitative analysis.

This compound dissolves in aqueous ammonia. Large crystals of silver phosphate form upon gradual evaporation of such ammoniacal solutions.

Its structure has been confirmed by X-ray crystallography.

The precipitation of silver phosphate is useful in traditional analytical chemistry. Precipitation of silver phosphate is also used in silver staining of biological materials (after reduction to silver metal) - as a magnifying agent for phosphate.

Silver phosphate also found use in early photography as a light sensitive agent.

Silver phosphate exhibits antibacterial properties.

Silver phosphate is a high (90%) quantum yield photocatalyst for the visible light photochemical splitting of water and for production of activated oxygen by the same method.