View source for 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 = <ref>{{RubberBible62nd|page=B-145}}.</ref>
| Formula = Ag<sub>3</sub>PO<sub>4</sub>
| MolarMass = 418.574 g/mol
| Appearance = Translucent yellow <br> becomes opaque or discolors when impure.
| Odor = odorless
| Density = 6.370 g/cm<sup>3</sup>
| MeltingPtC = 849
| BoilingPt = 
| Solubility = 0.00065 g/100 mL
| SolubilityProduct = 8.89{{e|&minus;17}}<ref name="crc">{{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}}</ref>
| MagSus = &minus;120.0·10<sup>−6</sup> cm<sup>3</sup>/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 [[Silver|Ag]]<sub>3</sub>[[Phosphorus|P]][[Oxygen|O]]<sub>4</sub>.

== 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]].<ref name="EB1911 21, p. 475">{{cite EB1911 |wstitle=Phosphates |volume=21 |page=475}}</ref> Its [[solubility product]] is 8.89×10<sup>−17</sup> mol<sup>4</sup>·dm<sup>−2</sup>.<ref>[http://www.solubilityofthings.com/water/ions_solubility/ksp_chart.php Ksp solubility constant for common salts] ''www.solubilityofthing.com''</ref><ref>[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''</ref> The precipitation reaction is analytically significant<ref>Inorganic 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]</ref> and can be used in qualitative or quantitative analysis.<ref name="prec">{{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 }}</ref>

This compound dissolves in aqueous [[ammonia]].<ref name="EB1911 21, p. 475"/> Large crystals of silver phosphate form upon gradual evaporation of such ammoniacal solutions.

Its structure has been confirmed by [[X-ray crystallography]].<ref>{{cite journal | author= R. Masse, I, Tordjman, A. Durif | title= Affinement de la Structure Cristalline du Monophosphate d'Argent Ag<sub>3</sub>PO<sub>4</sub>. 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 }}</ref>

== Uses ==
The precipitation of silver phosphate is useful in traditional [[analytical chemistry]].  Precipitation of silver phosphate is also used in [[silver stain]]ing of biological materials (after reduction to silver metal) - as a magnifying agent for phosphate.<ref>{{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]</ref>

Silver phosphate also found use in early photography as a light sensitive agent.<ref>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]</ref>

Silver phosphate exhibits antibacterial properties.<ref>[http://www.nanowerk.com/news/newsid=8997.php Nanocoated film as a bacteria killer] 23/1/2009, ''www.nanowerk.com''</ref>

==Research==
Silver phosphate is a high (90%) [[quantum yield]] [[photocatalyst]] for the visible light [[photolysis|photochemical splitting]] of water and for production of activated oxygen by the same method.<ref>{{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 }}</ref>

== Other silver phosphates ==
'''Silver pyrophosphate''' Ag<sub>4</sub>P<sub>2</sub>O<sub>7</sub> (CAS No. 13465-97-9)<ref>[http://www.chemicalbook.com/ChemicalProductProperty_EN_CB3421040.htm Silver pyrophosphate] ''www.chemicalbook.com''</ref> 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.<ref>[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''</ref> It has a density of 5.306 g/cm<sup>3</sup> and a melting point of 585&nbsp;°C.<ref name="bul">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]</ref> A hydrate also exists which decomposes at 110&nbsp;°C.<ref name="bul"/>

'''Silver metaphosphate''' (AgPO<sub>3</sub>) (CAS No. 13465-96-8)<ref>[http://www.chemicalbook.com/ChemicalProductProperty_EN_CB0263971.htm Silver metaphosphate] ''www.chemicalbook.com''</ref> is a white solid with a density of 6.370 g/cm<sup>3</sup> and a melting point of 482&nbsp;°C. A hydrate also exists which decomposes at 240&nbsp;°C.<ref name="bul"/>

== References ==
{{reflist}}

{{silver compounds}}
{{Phosphates}}

[[Category:Silver compounds]]
[[Category:Phosphates]]