Silver phosphate
Chemical compound
From Wikipedia, the free encyclopedia
Silver phosphate or silver orthophosphate is a light sensitive, yellow, water-insoluble chemical compound composed of silver and phosphate ions of formula Ag3PO4.
| |
 | |
| Names | |
|---|---|
| IUPAC name
Silver(I) phosphate | |
Other names
| |
| Identifiers | |
3D model (JSmol) |
|
| ChemSpider | |
| ECHA InfoCard | 100.029.135 |
| EC Number |
|
PubChem CID |
|
| UNII | |
CompTox Dashboard (EPA) |
|
| |
| |
| Properties[1] | |
| Ag3PO4 | |
| Molar mass | 418.574 g/mol |
| Appearance | Translucent yellow becomes opaque or discolors when impure. |
| Odor | odorless |
| Density | 6.370 g/cm3 |
| Melting point | 849 °C (1,560 °F; 1,122 K) |
| 0.00065 g/100 mL | |
Solubility product (Ksp) |
8.89×10−17[2] |
| −120.0·10−6 cm3/mol | |
| Structure | |
| cubic | |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | non-flammable |
| Safety data sheet (SDS) | Sigma-Alrdich |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
Synthesis, reactions and properties
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.[3] Its solubility product is 8.89×10−17 mol4·dm−2.[4][5] The precipitation reaction is analytically significant[6] and can be used in qualitative or quantitative analysis.[7]
This compound dissolves in aqueous ammonia.[3] Large crystals of silver phosphate form upon gradual evaporation of such ammoniacal solutions.
Its structure has been confirmed by X-ray crystallography.[8]
Uses
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.[9]
Silver phosphate also found use in early photography as a light sensitive agent.[10]
Silver phosphate exhibits antibacterial properties.[11]
Research
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.[12]
Other silver phosphates
Silver pyrophosphate Ag4P2O7 (CAS No. 13465-97-9)[13] can be prepared as a white precipitate from reaction of silver(I) and pyrophosphate ions. Like silver orthophosphate it is light sensitive. Silver orthophosphate turns red on exposure to light.[14] It has a density of 5.306 g/cm3 and a melting point of 585 °C.[15] A hydrate also exists which decomposes at 110 °C.[15]
Silver metaphosphate (AgPO3) (CAS No. 13465-96-8)[16] is a white solid with a density of 6.370 g/cm3 and a melting point of 482 °C. A hydrate also exists which decomposes at 240 °C.[15]