Silver phosphate or silver orthophosphate is a light sensitive, yellow, water-insoluble chemical compound composed of silver and phosphate ions of formula Ag3PO4.
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. Its solubility product is 8.89×10−17 mol4·dm−2.Ksp solubility constant for common salts www.solubilityofthing.comSOLUBILITY PRODUCT CONSTANTS www.ktf-split.hr The precipitation reaction is analytically significantInorganic chemistry, Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, Academic Press, 2001 p.721 Google Books excerpt 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.
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. Free version
Silver phosphate also found use in early photography as a light sensitive agent.Cassell's cyclopaedia of photography, Bernard Edward Jones, Ayer Publishing, 1973, p.401 'Phosphate plates and papers', googlebooks link
Silver phosphate exhibits antibacterial properties.Nanocoated film as a bacteria killer 23/1/2009, www.nanowerk.com
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.
Other silver phosphates Silver pyrophosphate Ag4P2O7 (CAS No. 13465-97-9)Silver pyrophosphate www.chemicalbook.com 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.Silver Compounds p.5, section 2.22, from Kirk-Othmer Encyclopedia of Chemical Technology, Authors: SAMUEL F. ETRIS (The Silver Institute), C. ROBERT CAPPEL (Eastman Kodak Company), via www.scribd.com It has a density of 5.306 g/cm3 and a melting point of 585 °C.Bulletin of the National Research Council, National Research Council (U.S.A), 1950, pp.56-57 google books link A hydrate also exists which decomposes at 110 °C.
Silver metaphosphate (AgPO3) (CAS No. 13465-96-8)Silver metaphosphate www.chemicalbook.com 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.
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