Silver oxide

Silver oxide
Silver(I) oxide structure in unit cell
Silver(I) oxide powder
Names
IUPAC name
Silver(I) oxide
Other names
Silver rust, Argentous oxide, Silver monoxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.039.946 Edit this at Wikidata
EC Number
  • 243-957-1
MeSH silver+oxide
RTECS number
  • VW4900000
UNII
  • InChI=1S/2Ag.O/q2*+1;-2 ☒N
    Key: NDVLTYZPCACLMA-UHFFFAOYSA-N ☒N
  • InChI=1S/2Ag.O/q2*+1;-2
    Key: NDVLTYZPCACLMA-UHFFFAOYSA-N
  • [O-2].[Ag+].[Ag+]
Properties
Ag2O
Molar mass 231.735 g·mol−1
Appearance Black/ brown cubic crystals
Odor Odorless
Density 7.14 g/cm3
Melting point 300 °C (572 °F; 573 K) decomposes from ≥200 °C
0.013 g/L (20 °C)
0.025 g/L (25 °C)
0.053 g/L (80 °C)
Solubility product (Ksp) of AgOH
1.52·10−8 (20 °C)
Solubility Soluble in acid, alkali
Insoluble in ethanol
−134.0·10−6 cm3/mol
Structure
Cubic
Pn3m, 224
Thermochemistry
65.9 J/mol·K
122 J/mol·K
−31 kJ/mol
−11.3 kJ/mol
Hazards
GHS labelling:
GHS03: OxidizingGHS07: Exclamation mark
Danger
H272, H315, H319, H335
P220, P261, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
2
0
1
Lethal dose or concentration (LD, LC):
2.82 g/kg (rats, oral)
Related compounds
Related compounds
Silver(I,III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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

Silver(I) oxide produced by reacting lithium hydroxide with a very dilute silver nitrate solution

Silver oxide can be prepared by combining aqueous solutions of silver nitrate and an alkali hydroxide. This reaction does not afford appreciable amounts of silver hydroxide due to the favorable energetics for the following reaction:

(pK = 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 with Cu2O. It "dissolves" in solvents that degrade it. It is slightly soluble in water due to the formation of the ion Ag(OH)2 and possibly related hydrolysis products. It is soluble in ammonia solution, producing active compound of Tollens' reagent. A slurry of Ag2O is readily attacked by acids:

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.

Despite the photosensitivity of many silver compounds, silver oxide is not photosensitive, although it readily decomposes at temperatures above 280 °C.

Applications

This oxide is used in silver-oxide batteries. In organic chemistry, silver oxide is used as a mild oxidizing agent. For example, it oxidizes aldehydes to carboxylic acids. Such reactions often work best when the silver oxide is prepared in situ from silver nitrate and alkali hydroxide.


This page was last updated at 2023-10-30 18:15 UTC. Update now. View original page.

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