Silver phosphate
{{Chembox
| ImageFile = Fosforečnan stříbrný.PNG
| ImageSize =
| ImageAlt =
| ImageFile1 = Ag3PO4_crystal_structure.png
| IUPACName = Silver(I) phosphate
| PIN =
| OtherNames = phosphoric acid, silver(I) salt; argentous phosphate; silver phosphate
|Section1={{Chembox Identifiers
| CASNo = 7784-09-0
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = ZL6T4Y1XP8
| EINECS = 232-049-0
| ChemSpiderID = 140592
| PubChem = 159913
| InChI = 1S/3Ag.H3O4P/c;;;1-5(2,3)4/h;;;(H3,1,2,3,4)/q3*+1;/p-3
| InChIKey = FJOLTQXXWSRAIX-UHFFFAOYSA-K
| SMILES = [O-]P(=O)([O-])[O-].[Ag+].[Ag+].[Ag+]
}}
|Section2={{Chembox Properties
| Properties_ref = {{RubberBible62nd|page=B-145}}.
| Formula = Ag3PO4
| MolarMass = 418.574 g/mol
| Appearance = Translucent yellow
becomes opaque or discolors when impure.
| Odor = odorless
| Density = 6.370 g/cm3
| MeltingPtC = 849
| BoilingPt =
| Solubility = 0.00065 g/100 mL
| SolubilityProduct = 8.89{{e|−17}}{{cite book |author1=John Rumble |title=CRC Handbook of Chemistry and Physics |date=June 18, 2018 |publisher=CRC Press |isbn=978-1138561632 |pages=5–189|edition=99 |language=English}}
| MagSus = −120.0·10−6 cm3/mol
}}
|Section3={{Chembox Structure
| CrystalStruct = cubic
}}
|Section7={{Chembox Hazards
| ExternalSDS = [http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=PL&language=EN-generic&productNumber=337382&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F337382%3Flang%3Dpl Sigma-Alrdich]
| MainHazards =
| NFPA-H = 2 | NFPA-F = 0 | NFPA-R = 0
| FlashPt = non-flammable
| AutoignitionPt = }}
}}
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.{{cite EB1911 |wstitle=Phosphates |volume=21 |page=475}} Its solubility product is 8.89×10−17 mol4·dm−2.[http://www.solubilityofthings.com/water/ions_solubility/ksp_chart.php Ksp solubility constant for common salts] www.solubilityofthing.com[http://www.ktf-split.hr/periodni/en/abc/kpt.html SOLUBILITY PRODUCT CONSTANTS] {{webarchive|url=https://web.archive.org/web/20120615020049/http://www.ktf-split.hr/periodni/en/abc/kpt.html |date=2012-06-15 }} www.ktf-split.hr The precipitation reaction is analytically significantInorganic chemistry, Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, Academic Press, 2001 p.721 [https://books.google.com/books?id=vEwj1WZKThEC&pg=PA721 Google Books excerpt] and can be used in qualitative or quantitative analysis.{{cite journal | title = Precipitation of Silver Phosphate from Homogenous Solution | author = F.H. Firsching | journal = Anal. Chem. | volume = 33 | pages = 873–874 | year = 1961 | doi = 10.1021/ac60175a018 | issue = 7 }}
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.{{cite journal | author= R. Masse, I, Tordjman, A. Durif | title= Affinement de la Structure Cristalline du Monophosphate d'Argent Ag3PO4. Existence d'une Forme Haute Témperature | journal= Zeitschrift für Kristallographie | volume= 144 | year= 1976 | issue= 1–6 | pages= 76–81 | doi= 10.1524/zkri.1976.144.1-6.76| bibcode= 1976ZK....144...76M }}
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.{{Cite journal| last1 = Taichman | first1 = R. S.| last2 = Hauschka | first2 = P. V.| title = Effects of interleukin-1? And tumor necrosis factor-? On osteoblastic expression of osteocalcin and mineralized extracellular matrix in vitro| journal = Inflammation| volume = 16| issue = 6| pages = 587–601| year = 1992| pmid = 1459694| doi = 10.1007/BF00919342| hdl = 2027.42/44508| s2cid = 21949509| url = https://deepblue.lib.umich.edu/bitstream/2027.42/44508/1/10753_2004_Article_BF00919342.pdf| hdl-access = free}} [http://deepblue.lib.umich.edu/bitstream/2027.42/44508/1/10753_2004_Article_BF00919342.pdf 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', [https://books.google.com/books?id=pqkR3Po010sC&dq=silver+phosphate&pg=PA401 googlebooks link]
Silver phosphate exhibits antibacterial properties.[http://www.nanowerk.com/news/newsid=8997.php 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.{{Cite journal| last1 = Yi | first1 = Z.| last2 = Ye | first2 = J.| last3 = Kikugawa | first3 = N.| last4 = Kako | first4 = T.| last5 = Ouyang | first5 = S.| last6 = Stuart-Williams | first6 = H.| last7 = Yang | first7 = H.| last8 = Cao | first8 = J.| last9 = Luo | first9 = W.| last10 = Li | first10 = Z.| last11 = Liu | first11 = Y.| last12 = Withers | first12 = R. L.| title = An Orthophosphate Semiconductor with Photooxidation Properties under Visible-Light Irradiation| journal = Nature Materials| volume = 9| issue = 7| pages = 559–564| year = 2010| pmid = 20526323| doi = 10.1038/nmat2780|bibcode = 2010NatMa...9..559Y }}
Other silver phosphates
Silver pyrophosphate Ag4P2O7 (CAS No. 13465-97-9)[http://www.chemicalbook.com/ChemicalProductProperty_EN_CB3421040.htm 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.[https://www.scribd.com/doc/30122611/Silver-Compounds Silver Compounds] {{Webarchive|url=https://web.archive.org/web/20131203180846/http://www.scribd.com/doc/30122611/Silver-Compounds |date=2013-12-03 }} 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 [https://books.google.com/books?id=8SUrAAAAYAAJ&dq=silver+phosphate&pg=PA57 google books link] A hydrate also exists which decomposes at 110 °C.
Silver metaphosphate (AgPO3) (CAS No. 13465-96-8)[http://www.chemicalbook.com/ChemicalProductProperty_EN_CB0263971.htm 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.