Silver (I) oxide

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Crystal structure
Crystal structure of silver (I) oxide
__ Ag +      __ O 2−
Surname Silver (I) oxide
other names
  • Disilver oxide
Ratio formula Ag 2 O
Brief description

heavy, almost black, velvety powder

External identifiers / databases
CAS number 20667-12-3
EC number 243-957-1
ECHA InfoCard 100,039,946
PubChem 9794626
ChemSpider 7970393
Wikidata Q407815
Molar mass 231.74 g mol −1
Physical state



7.2 g cm −3 (20 ° C)

Melting point

130 ° C (decomposition)


practically insoluble in water

safety instructions
GHS labeling of hazardous substances
03 - Oxidising 05 - Corrosive 09 - Dangerous for the environment


H and P phrases H: 271-318-410
P: 210-280-305 + 351 + 338 + 310-370 + 378-371 + 380 + 375

0.01 mg m −3

Toxicological data

2820 mg kg −1 ( LD 50ratoral )

Thermodynamic properties
ΔH f 0

−31.1 kJ / mol

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Silver (I) oxide (Ag 2 O) is a chemical compound from the group of oxides .

Extraction and presentation

Silver (I) oxide is the reaction product of the noble metal silver with oxygen .

Sodium hydroxide or potassium hydroxide is added to the silver nitrate solution . Silver oxide precipitates in alkaline as a brown precipitate :


Silver (I) oxide is a brown powder that darkens when exposed to sunlight. Moist silver (I) oxide is very insensitive to light and decomposes somewhat when it dries. It has a crystal structure of the Cu 2 O type with the space group Pn 3 m (space group number 224) (a = 475.2 pm) and an enthalpy of formation of −30.5 kJ / mol. Slurries of silver oxide in water have a markedly alkaline reaction, since silver and hydroxide ions are formed in reverse of the above reaction. Template: room group / 224

In reverse of the synthesis reaction, silver (I) oxide is broken down again into the elements silver and oxygen when heated ( thermolysis ).

In the air, silver (I) oxide reacts with carbon dioxide to form silver carbonate :


In preparative organic chemistry, silver (I) oxide is used in a variant of the Williamson ether synthesis .

Williamson ether synthesis using silver (I) oxide

Silver (I) oxide is contained in thermal paste to conduct the processor heat to the heat sinks in the computer, as it has a high thermal conductivity .

Silver (I) oxide is part of the silver oxide-zinc battery that is used in wristwatches and other small devices.

Individual evidence

  1. Entry on SILVER OXIDE in the CosIng database of the EU Commission, accessed on May 4, 2020.
  2. Entry on silver oxides. In: Römpp Online . Georg Thieme Verlag, accessed on September 19, 2014.
  3. a b c d e f g h Entry on silver (I) oxide in the GESTIS substance database of the IFA , accessed on November 18, 2018(JavaScript required) .
  4. David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-4.
  5. Georg Brauer (Ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 998.
  6. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 .
  7. Masato Tanabe and Richard H. Peters: (R, S) -Mevalonolactone-2- 13 C In: Organic Syntheses . 60, 1981, p. 92, doi : 10.15227 / orgsyn.060.0092 ; Coll. Vol. 7, 1990, p. 386 ( PDF ).