Silver oxide is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula Ag₂O. It is a fine black or dark brown powder that is used to prepare other

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

compounds.

Preparation

Silver oxide can be prepared by combining aqueous solutions of

silver nitrate Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar causti ...

and an

alkali hydroxide The alkali hydroxides are a class of chemical compounds which are composed of an alkali metal cation and the hydroxide anion (OH−). The alkali hydroxides are: * Lithium hydroxide (LiOH) * Sodium hydroxide (NaOH) * Potassium hydroxide (KOH) *Rubi ...

. This reaction does not afford appreciable amounts of silver hydroxide due to the favorable energetics for the following reaction: :2 AgOH -> Ag2O + H2O ( p''K'' = 2.875) 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.

Structure and properties

Ag₂O features linear, two-coordinate Ag centers linked by tetrahedral oxides. It is

isostructural Isostructural chemical compounds have similar chemical structures. " Isomorphous" when used in the relation to crystal structures is not synonymous: in addition to the same atomic connectivity that characterises isostructural compounds, isomorphous ...

with Cu₂O. It "dissolves" in solvents that degrade it. It is slightly soluble in water due to the formation of the ion and possibly related hydrolysis products. It is soluble in

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

solution, producing active compound of

Tollens' reagent Tollens' reagent (chemical formula Ag(NH3)2OH) is a chemical reagent used to distinguish between aldehydes and ketones along with some alpha-hydroxy ketones which can tautomerize into aldehydes. The reagent consists of a solution of silver nit ...

. A slurry of Ag₂O is readily attacked by acids: :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 Silver chloride is a chemical compound with the chemical formula Ag Cl. This white crystalline solid is well known for its low solubility in water (this behavior being reminiscent of the chlorides of Tl+ and Pb2+). Upon illumination or heating, ...

, 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, although it readily decomposes at temperatures above 280 °C.Merck Index of Chemicals and Drugs
, 14th ed. monograph 8521

Applications

This oxide is used in silver-oxide batteries. In organic chemistry, silver oxide is used as a mild

oxidizing agent An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxi ...

. For example, it oxidizes

aldehydes In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

to carboxylic acids. Such reactions often work best when the silver oxide is prepared ''in situ'' from

and

References

External links

Annealing of Silver Oxide
– Demonstration experiment: Instruction and video {{Silver compounds Silver compounds Transition metal oxides