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.

Not to be confused with Silver hexafluorophosphate.
Silver phosphate
Names
IUPAC name
Silver(I) phosphate
Other names
phosphoric acid, silver(I) salt; argentous phosphate; silver phosphate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.135
EC Number
  • 232-049-0
UNII
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
−120.0·10−6 cm3/mol
Structure
cubic
Hazards
Safety data sheet Sigma-Alrdich
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
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

Synthesis, reactions and properties

Silver phosphate is formed as a yellow precipitate by the reaction between a soluble silver compound, such as silver nitrate with a soluble orthophosphate;[2] its solubility product is 8.89×10−17 mol4·dm−12.[3][4] The precipitation reaction is analytically significant[5] and can be used in qualitative or quantitative tests for phosphates.

This compound is dissolved by nitric acid or by ammonia.[2] 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.[6] Depending on the method of preparation different crystal forms of silver phosphate can be produced of the same lattice structure.[6]

Uses

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.[7]

Silver phosphate also found use in early photography as a light sensitive agent.[8]

In 2010, silver phosphate was reported as having a high (90%) quantum yield as a photocatalyst for the visible light photochemical splitting of water, and for production of activated oxygen by the same method.[9][10]

Silver phosphate is also a potential material for incorporating silver ion antibacterial properties into materials.[11]

Other silver phosphates

Silver pyrophosphate Ag4P2O7 (CAS No. 13465-97-9)[12] 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.[13] It has a density of 5.306 g/cm3 and a melting point of 585 °C.[14] A hydrate also exists which decomposes at 110 °C.[14]

Silver metaphosphate (AgPO3) (CAS No. 13465-96-8)[15] 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.[14]

References
  1. Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. B-145. ISBN 0-8493-0462-8..
  2. Chisholm, Hugh, ed. (1911). "Phosphates" . Encyclopædia Britannica. 21 (11th ed.). Cambridge University Press. p. 475.
  3. Ksp solubility constant for common salts www.solubilityofthing.com
  4. SOLUBILITY PRODUCT CONSTANTS Archived 2012-06-15 at the Wayback Machine www.ktf-split.hr
  5. Inorganic chemistry , Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman , Academic Press , 2001] p.721 Google Books excerpt
  6. F.H. Firsching (1961). "Precipitation of Silver Phosphate from Homogenous Solution". Anal. Chem. 33 (7): 873–874. doi:10.1021/ac60175a018.
  7. Taichman, R. S.; Hauschka, P. V. (1992). "Effects of interleukin-1? And tumor necrosis factor-? On osteoblastic expression of osteocalcin and mineralized extracellular matrix in vitro" (PDF). Inflammation. 16 (6): 587–601. doi:10.1007/BF00919342. hdl:2027.42/44508. PMID 1459694. S2CID 21949509. Free version
  8. Cassell's cyclopaedia of photography , Bernard Edward Jones , Ayer Publishing , 1973 , p.401 'Phosphate plates and papers' , googlebooks link
  9. Yi, Z.; Ye, J.; Kikugawa, N.; Kako, T.; Ouyang, S.; Stuart-Williams, H.; Yang, H.; Cao, J.; Luo, W.; Li, Z.; Liu, Y.; Withers, R. L. (2010). "An orthophosphate semiconductor with photooxidation properties under visible-light irradiation". Nature Materials. 9 (7): 559–564. Bibcode:2010NatMa...9..559Y. doi:10.1038/nmat2780. PMID 20526323.
  10. Discovery of a Novel High Activity Photocatalyst Material: A Great Step Toward the Realization of Artificial Photosynthesis Discovery of a Revolutionary Oxidation Property in Silver Phosphate with Quantum Yield of Approximately 90% in Visible Light , 2010/06/07 , press release , National Institute for Materials Science (NIMS) Japan , www.nims.go.jp
  11. Nanocoated film as a bacteria killer 23/1/2009 , www.nanowerk.com
  12. Silver pyrophosphate www.chemicalbook.com
  13. 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
  14. Bulletin of the National Research Council , National Research Council (U.S.A) , 1950 , pp.56-57 google books link
  15. Silver metaphosphate www.chemicalbook.com
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