Silver phosphate

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Not to be confused with Silver hexafluorophosphate.
Silver phosphate
Fosforečnan stříbrný.PNG
Identifiers
CAS number 7784-09-0
PubChem 159913
ChemSpider 140592
EC number 232-049-0
Jmol-3D images Image 1
Properties[1]
Molecular formula Ag3O4P
Molar mass 418.58 g mol−1
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
Structure
Crystal structure cubic
Hazards
MSDS Sigma-Alrdich
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point non-flammable
Except where noted otherwise, 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.

Synthesis, reactions and properties[edit]

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 mol4dm−12.[3][4] The precipitation reaction is analytically significant[5] and can be used to in qualitatively 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[edit]

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[edit]

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 5.306g/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 6.370g/cm3 and a melting point of 482 °C. A hydrate also exists which decomposes at 240 °C.[14]

References[edit]

  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. ^ a b Phosphates www.1911encyclopedia.org
  3. ^ Ksp solubility constant for common salts www.solubilityofthing.com
  4. ^ SOLUBILITY PRODUCT CONSTANTS www.ktf-split.hr
  5. ^ Inorganic chemistry , Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman , Academic Press , 2001] p.721 Google Books excerpt
  6. ^ a b F.H. Firsching (1961). "Precipitation of Silver Phosphate from Homogenous Solution". Anal. Chem. 33 (7): 873. 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". Inflammation 16 (6): 587–601. doi:10.1007/BF00919342. PMID 1459694.  edit 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.  edit
  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. ^ a b c 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