Silver oxide#Preparation
{{about|silver(I) oxide|the mixed-valence oxide|Silver(I,III) oxide}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 440120975
| ImageFile = Silver(I)-oxide-unit-cell-3D-bs-17.png
| ImageSize =
| ImageCaption = Unit cell
| ImageName = Silver(I) oxide structure in unit cell
| ImageFile1 = Silver(I)-oxide-xtal-3x3x3-3D-bs-17.png
| ImageCaption1 = Crystal packing
| ImageFile2 = Silver oxide.jpg
| ImageName2 = Silver(I) oxide powder
| IUPACName = Silver(I) oxide
| OtherNames = Silver rust, Argentous oxide, Silver monoxide
| Section1 = {{Chembox Identifiers
| Abbreviations =
| CASNo = 20667-12-3
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 897WUN6G6T
| RTECS = VW4900000
| PubChem = 9794626
| ChemSpiderID = 7970393
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| EINECS = 243-957-1
| MeSHName = silver+oxide
| SMILES = [O-2].[Ag+].[Ag+]
| StdInChI = 1S/2Ag.O/q2*+1;-2
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| InChI = 1S/2Ag.O/q2*+1;-2
| StdInChIKey = NDVLTYZPCACLMA-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| InChIKey = NDVLTYZPCACLMA-UHFFFAOYSA-N
}}
| Section2 = {{Chembox Properties
| Ag=2 | O=1
| Appearance = Black/ brown cubic crystals
| Density = 7.14 g/cm3
| MeltingPtC = 300
| MeltingPt_notes = decomposes from ≥200 °C
| BoilingPtC =
| BoilingPt_notes =
| Solubility = 0.013 g/L (20 °C)
0.025 g/L (25 °C){{cite book|last = Lide|first = David R.|year = 1998|title = Handbook of Chemistry and Physics|edition = 81|location = Boca Raton, FL|publisher = CRC Press|isbn = 0-8493-0594-2|pages = 4–83}}
0.053 g/L (80 °C){{cite book|last = Perry|first = Dale L.|year = 1995|title = Handbook of Inorganic Compounds|edition = illustrated|publisher = CRC Press|isbn = 0849386713|pages = 354}}
| SolubilityProduct = 1.52·10−8 (20 °C)
| SolubilityProductAs = AgOH
| SolubleOther = Soluble in acid, alkali
Insoluble in ethanol
| pKa = 12.1 (estimated){{cite book|title=Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution|editor-first=D. D.|editor-last=Perrin|edition=2nd|series=IUPAC Chemical Data|issue=29|publisher=Pergamon|location=Oxford|year=1982|publication-date=1984|orig-date=1969|lccn=82-16524|isbn=0-08-029214-3|at=Entry 210}}
| MagSus = −134.0·10−6 cm3/mol }}
| Section3 = {{Chembox Structure
| CrystalStruct = Cubic
| SpaceGroup = Pn{{overline|3}}m, 224
| Coordination =
| MolShape =
| Dipole =
}}
| Section4 = {{Chembox Thermochemistry
| DeltaHf = −31 kJ/mol{{cite book|author = Zumdahl, Steven S.|title = Chemical Principles 6th Ed.|publisher = Houghton Mifflin Company|year = 2009|isbn = 978-0-618-94690-7|page = A23}}
| DeltaGf = −11.3 kJ/mol{{Cite web|url=http://chemister.ru/Database/properties-en.php?dbid=1&id=4098|title = Silver oxide}}
}}
| Section7 = {{Chembox Hazards
| ExternalSDS =
| GHSPictograms = {{GHS03}}{{GHS07}}{{Sigma-Aldrich|id=226831|name=Silver(I) oxide|accessdate=2014-06-07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|272|315|319|335}}
| PPhrases = {{P-phrases|220|261|305+351+338}}
| MainHazards =
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 1
| LD50 = 2.82 g/kg (rats, oral)
}}
| Section8 = {{Chembox Related
| OtherAnions =
| OtherCations =
| OtherFunction =
| OtherFunction_label =
| OtherCompounds = Silver(I,III) oxide
}}
}}
Silver oxide is the chemical compound with the formula Ag2O. It is a fine black or dark brown powder that is used to prepare other silver compounds.
Preparation
File:Silver(I) oxide.JPG with a very dilute silver nitrate solution]]
Silver oxide can be prepared by combining aqueous solutions of silver nitrate and an alkali hydroxide.O. Glemser and H. Sauer "Silver Oxide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1037.{{OrgSynth | title = 4-Iodoveratrole | author = Janssen, D. E.; Wilson, C. V. | collvol = 4 | collvolpages = 547 | year = 1963 | prep = CV4P0547}} This reaction does not afford appreciable amounts of silver hydroxide due to the favorable energetics for the following reaction:Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}.
:{{chem2 | 2 AgOH -> Ag2O + H2O }}{{spaces|4}}(pK = 2.875{{cite journal | doi = 10.3891/acta.chem.scand.14-0717 |author1=Biedermann, George |author2=Sillén, Lars Gunnar | title = Studies on the Hydrolysis of Metal Ions. Part 30. A Critical Survey of the Solubility Equilibria of Ag2O | year = 1960 | journal = Acta Chemica Scandinavica | volume = 13 | pages = 717–725| doi-access = free }})
With suitably controlled conditions, this reaction can be used to prepare Ag2O powder with properties suitable for several uses including as a fine grained conductive paste filler.{{Cite patent|country=US|number=20050050990A1|title=Fine-grain silver oxide powder|status=|pubdate=2005-03-10|invent1=Harigae|invent2=Shoji|inventor1-first=Kenichi|inventor2-first=Yoshiyuki}}
Structure and properties
Ag2O features linear, two-coordinate Ag centers linked by tetrahedral oxides. It is isostructural with Cu2O. It "dissolves" in solvents that degrade it. It is slightly soluble in water due to the formation of the ion {{Chem2|Ag(OH)2-}} and possibly related hydrolysis products.{{cite book |author1=Cotton, F. Albert |author2-link=Geoffrey Wilkinson |author2=Wilkinson, Geoffrey | title=Advanced Inorganic Chemistry (2nd Ed.) | publisher=New York:Interscience |page=1042| year=1966|author1-link=F. Albert Cotton }} It is soluble in ammonia solution, producing active compound of Tollens' reagent. A slurry of Ag2O is readily attacked by acids:
:{{chem2 | Ag2O + 2 HX -> 2 AgX + H2O }}
where HX = HF, HCl, HBr, HI, or CF3COOH. It will also react with solutions of alkali chlorides to precipitate silver chloride, leaving a solution of the corresponding alkali hydroxide.General Chemistry by Linus Pauling, 1970 Dover ed. p703-704
Despite the photosensitivity of many silver compounds, silver oxide is not photosensitive,{{Cite journal|last1=Herley|first1=P. J.|last2=Prout|first2=E. G.|date=1960-04-01|title=The Thermal Decomposition of Silver Oxide|url=https://doi.org/10.1021/ja01492a006|journal=Journal of the American Chemical Society|volume=82|issue=7|pages=1540–1543|doi=10.1021/ja01492a006|issn=0002-7863|url-access=subscription}} although it readily decomposes at temperatures above 280 °C.[http://themerckindex.cambridgesoft.com/TheMerckIndex/default.asp?formgroup=basenp_form_group&dataaction=db&dbname=TheMerckIndex Merck Index of Chemicals and Drugs] {{webarchive|url=https://web.archive.org/web/20090201140752/http://themerckindex.cambridgesoft.com/TheMerckIndex/default.asp?formgroup=basenp_form_group&dataaction=db&dbname=TheMerckIndex |date=2009-02-01 }}, 14th ed. monograph 8521
Applications
This oxide is used in silver-oxide batteries.{{Cite web |date=2009-12-20 |title=Duracell PROCELL: The Chemistries: Silver Oxide |url=http://www.duracell.com/procell/chemistries/silver.asp |access-date=2024-05-12 |archive-url=https://web.archive.org/web/20091220201115/http://www.duracell.com/procell/chemistries/silver.asp |archive-date=2009-12-20 }} In organic chemistry, silver oxide is used as a mild oxidizing agent.{{Cite book |last=裴 |first=坚 |title=基础有机化学 |edition=4th |publication-date=2017 |pages=1064 |language=Chinese |trans-title=Basic Organic Chemistry}} For example, it oxidizes aldehydes to carboxylic acids.{{Cite journal |last1=Chakraborty |first1=Debashis |last2=Gowda |first2=Ravikumar R. |last3=Malik |first3=Payal |date=2009 |title=Silver nitrate-catalyzed oxidation of aldehydes to carboxylic acids by H2O2 |url=https://linkinghub.elsevier.com/retrieve/pii/S0040403909017663 |journal=Tetrahedron Letters |language=en |volume=50 |issue=47 |pages=6553–6556 |doi=10.1016/j.tetlet.2009.09.044|url-access=subscription }}
References
{{Reflist}}
External links
{{Commons category|Silver(I) oxide}}
- [http://www.job-stiftung.de/index.php?id=31,163,0,0,1,0 Annealing of Silver Oxide] – Demonstration experiment: Instruction and video
{{Oxides}}
{{Silver compounds}}