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Names | |
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IUPAC name Silver(I) oxide | |
Other names Silver rust, Argentous oxide, Silver monoxide | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.039.946 |
EC Number |
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MeSH | silver+oxide |
PubChem CID | |
RTECS number |
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UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
Ag2O | |
Molar mass | 231.735 g·mol−1 |
Appearance | Black/ brown cubic crystals |
Odor | Odorless [1] |
Density | 7.14 g/cm3 |
Melting point | 300 °C (572 °F; 573 K) decomposes from ≥200 °C [2] [3] |
0.013 g/L (20 °C) 0.025 g/L (25 °C) [4] 0.053 g/L (80 °C) [2] | |
Solubility product (Ksp) of AgOH | 1.52·10−8 (20 °C) |
Solubility | Soluble in acid, alkali Insoluble in ethanol [4] |
−134.0·10−6 cm3/mol | |
Structure | |
Cubic | |
Pn3m, 224 | |
Thermochemistry | |
Heat capacity (C) | 65.9 J/mol·K [4] |
Std molar entropy (S⦵298) | 122 J/mol·K [5] |
Std enthalpy of formation (ΔfH⦵298) | −31 kJ/mol [5] |
Gibbs free energy (ΔfG⦵) | −11.3 kJ/mol [3] |
Hazards | |
GHS labelling: | |
[6] | |
Danger | |
H272, H315, H319, H335 [6] | |
P220, P261, P305+P351+P338 [6] | |
NFPA 704 (fire diamond) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 2.82 g/kg (rats, oral) [1] |
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). |
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.
Silver oxide can be prepared by combining aqueous solutions of silver nitrate and an alkali hydroxide. [7] [8] This reaction does not afford appreciable amounts of silver hydroxide due to the favorable energetics for the following reaction: [9]
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. [11]
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. [12] 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. [12] [13]
Despite the photosensitivity of many silver compounds, silver oxide is not photosensitive, [14] although it readily decomposes at temperatures above 280 °C. [15]
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.
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. The corresponding electrically neutral compound HO• is the hydroxyl radical. The corresponding covalently bound group –OH of atoms is the hydroxy group. Both the hydroxide ion and hydroxy group are nucleophiles and can act as catalysts in organic chemistry.
In chemistry, iron(III) refers to the element iron in its +3 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe3+.
Silver nitrate is an inorganic compound with chemical formula AgNO
3. 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 caustic because silver was called luna by ancient alchemists who associated silver with the moon. In solid silver nitrate, the silver ions are three-coordinated in a trigonal planar arrangement.
Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated forms which are both hygroscopic. They feature iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while all forms are mild oxidizing agent. It is used as a water cleaner and as an etchant for metals.
Potassium ferrate is the chemical compound with the formula K2FeO4. This purple salt is paramagnetic, and is a rare example of an iron(VI) compound. In most of its compounds, iron has the oxidation state +2 or +3 (Fe2+ or Fe3+). Reflecting its high oxidation state, FeO2−4 is a powerful oxidizing agent.
Tollens' reagent 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 nitrate, ammonium hydroxide and some sodium hydroxide. It was named after its discoverer, the German chemist Bernhard Tollens. A positive test with Tollens' reagent is indicated by the precipitation of elemental silver, often producing a characteristic "silver mirror" on the inner surface of the reaction vessel.
Ferrate(VI) is the inorganic anion with the chemical formula [FeO4]2−. It is photosensitive, contributes a pale violet colour to compounds and solutions containing it and is one of the strongest water-stable oxidizing species known. Although it is classified as a weak base, concentrated solutions containing ferrate(VI) are corrosive and attack the skin and are only stable at high pH. It is similar to the somewhat more stable permanganate.
Silver carbonate is the chemical compound with the formula Ag2CO3. This salt is yellow but typical samples are grayish due to the presence of elemental silver. It is poorly soluble in water, like most transition metal carbonates.
Basic oxides are oxides that show basic properties in opposition to acidic oxides and that either
Palladium(II) oxide is the inorganic compound of formula PdO. It is the only well characterised oxide of palladium. It is prepared by treating the metal with oxygen. Above about 900 °C, the oxide reverts to palladium metal and oxygen gas. It is not attacked by acids.
Cadmium nitrate describes any of the related members of a family of inorganic compounds with the general formula , the most commonly encountered form being the tetrahydrate. The anhydrous form is volatile, but the others are colourless crystalline solids that are deliquescent, tending to absorb enough moisture from the air to form an aqueous solution. Like other cadmium compounds, cadmium nitrate is known to be carcinogenic.
Iron(III) nitrate, or ferric nitrate, is the name used for a series of inorganic compounds with the formula Fe(NO3)3.(H2O)n. Most common is the nonahydrate Fe(NO3)3.(H2O)9. The hydrates are all pale colored, water-soluble paramagnetic salts.
Silver is a relatively unreactive metal, although it can form several compounds. The common oxidation states of silver are (in order of commonness): +1 (the most stable state; for example, silver nitrate, AgNO3); +2 (highly oxidising; for example, silver(II) fluoride, AgF2); and even very rarely +3 (extreme oxidising; for example, potassium tetrafluoroargentate(III), KAgF4). The +3 state requires very strong oxidising agents to attain, such as fluorine or peroxodisulfate, and some silver(III) compounds react with atmospheric moisture and attack glass. Indeed, silver(III) fluoride is usually obtained by reacting silver or silver monofluoride with the strongest known oxidizing agent, krypton difluoride.
Sodium bismuthate is an inorganic compound, and a strong oxidiser with chemical formula NaBiO3. It is somewhat hygroscopic, but not soluble in cold water, which can be convenient since the reagent can be easily removed after the reaction. It is one of the few water insoluble sodium salts. Commercial samples may be a mixture of bismuth(V) oxide, sodium carbonate and sodium peroxide.
Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.
Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.
Chromium(III) hydroxide is a gelatinous green inorganic compound with the chemical formula Cr(OH)3. It is a polymer with an undefined structure and low solubility. It is amphoteric, dissolving in both strong alkalis and strong acids.
Germanium(II) hydroxide, normally written as Ge(OH)2, is a poorly characterised compound, sometimes called hydrous germanium(II) oxide or germanous hydroxide. It was first reported by Winkler in 1886.
Neptunium compounds are compounds containg the element neptunium (Np). Neptunium has five ionic oxidation states ranging from +3 to +7 when forming chemical compounds, which can be simultaneously observed in solutions. It is the heaviest actinide that can lose all its valence electrons in a stable compound. The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Neptunium metal is very reactive. Ions of neptunium are prone to hydrolysis and formation of coordination compounds.
Technetium(IV) oxide, also known as technetium dioxide, is a chemical compound with the formula TcO2 which forms the dihydrate, TcO2·2H2O, which is also known as technetium(IV) hydroxide. It is a radioactive black solid which slowly oxidizes in air.
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: CS1 maint: multiple names: authors list (link); Collective Volume, vol. 4, p. 547