Silver phosphate

Silver phosphate

Names
IUPAC name Silver(I) phosphate
Other names phosphoric acid, silver(I) salt; argentous phosphate; silver phosphate
Identifiers
CAS Number	7784-09-0
3D model (JSmol)	Interactive image
ChemSpider	140592
ECHA InfoCard	100.029.135
EC Number	232-049-0
PubChem CID	159913
InChI InChI=1S/3Ag.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3 Key: FJOLTQXXWSRAIX-UHFFFAOYSA-K
SMILES [O-]P(=O)([O-])[O-].[Ag+].[Ag+].[Ag+]
Properties
Chemical formula	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)
Solubility in water	0.00065 g/100 mL
Magnetic susceptibility (χ)	−120.0·10−6 cm3/mol
Structure
Crystal structure	cubic
Hazards
Safety data sheet	Sigma-Alrdich
NFPA 704	0 2 0
Flash point	non-flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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 precipitate by the reaction between a soluble silver compound, such as silver nitrate with a soluble orthophosphate; its solubility product is 8.89×10⁻¹⁷ mol⁴dm⁻¹². The precipitation reaction is analytically significant and can be used in qualitative or quantitative tests for phosphates.

This compound is dissolved by nitric acid, or by ammonia. It can also be formed as large crystals by gradual loss of ammonia from an ammoniacal solution of silver phosphate; the reaction can be used in quantitative analysis of phosphate ions. Depending on the method of preparation different crystal forms of silver phosphate can be produced of the same lattice structure.

As well as being important in analytical chemistry, the 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.

In 2010, silver phosphate was reported as having a high (90%) quantum yield as a for the visible light photochemical splitting of water, and for production of activated oxygen by the same method.

Silver phosphate is also a potential material for incorporating silver ion antibacterial properties into materials.

Silver pyrophosphate Ag₄P₂O₇ (CAS No. 13465-97-9) 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. It has a density of 5.306g/cm³ and a melting point of 585 °C. A hydrate also exists which decomposes at 110 °C.

Silver metaphosphate (AgPO₃) (CAS No. 13465-96-8) is a white solid with a density of 6.370g/cm³ and a melting point of 482 °C. A hydrate also exists which decomposes at 240 °C.