What are common Compounds of Silver?

16 min read
Compounds of Silver

The electron configuration of silver

Compounds of silver form because of the electron configuration of the silver atom. The electronic structure of the silver atom is normally 2, 8, 18, 18, 1. The single outer electron may use for electrovalent combination, leaving the argentous ion, Ag+, with electron structure, 2, 8, 18, 18.

Do you like to know more about electron configuration?

Then check this out, Very informative article electron configurations of elements.

Compounds of Silver

It may also use as one electron of a shared pair in covalent combination. Silver Compounds so formed are also called argentous. The argentous ion can participate in both cationic and anionic complexes.examples of these will find in the following paragraphs.

Silver also exerts divalency, but only rarely. In this case, the electron structure changes to 2, 8, 18, 17, 2 and the corresponding silver ion Ag2+ that has the electron structure 2, 8, 18, 17.

Silver oxide, AgO and Silver fluoride, AgF2, are known as some complex organic derivatives or argentic silver, but all are unimportant.

So, Firstly, let’s have a look at the most important compound of silver, Silver oxide.

Silver Oxide

Silver oxide compounds
Silver oxide

Preparation of Silver oxide Compound

Method 01

Silver oxide is the main compound among the compounds of silver. Silver oxide precipitate as brown solid by the addition of a caustic alkali solution of silver nitrate.

2Ag+ + 2OH → Ag2O + H2O

The precipitate is probably hydrated to some extent but, if filtered, washed and dried at about 800C. This silver compound obtained as a black anhydrous powder.

Notice that caustic alkali solutions usually precipitate metallic hydroxide, silver hydroxide never produced in the above conditions, is too unstable. It said to be produced by alcoholic solutions of the above reagents at 300C.

Method 02

The addition of a little dilute aqueous ammonia to silver nitrate solution precipitates silver oxide as a brown solid.

2Ag+ + 2OH → Ag2O + H2O

Addition of an excess of ammonia then dissolves the precipitate by the formulation of a cationic complex between molecules of NH3 and the Silver ion, Ag+.

Ag+ + 2NH4OH [Ag(NH3)2]+ + 2H2O

If left to stand exposed to air, a solution of silver oxide in excess of ammonia slowly deposits a black powder, probably the nitride, Ag3N. It is explosive when dry and known as fulminating silver.

So, Its time to discuss the properties of silver oxide compound.

Silver oxide compound as an Oxidising agent

A solution of silver oxide compound In excess of aqueous ammonia, known as ammoniacal silver oxide (or nitrate), is a useful oxidising agent, especially with organic compounds. If shaken with acetaldehyde in a test tube and heated slowly, then the solution deposits a silver mirror on the side of the test tube. The aldehyde oxidises to acetic acid, which forms its salt, ammonium acetate. The reaction is,

Ag2O + CH3CHO + NH4OH 2Ag + CH3COONH4 + H2O

Properties of Silver oxide compound

Silver oxide is quite a strong base. It is slightly soluble in water, and the solution is alkaline. Consequently, silver does not form basic salts such as are common in cupric chemistry. Cupric oxide is a much weaker base.

In addition,

Silver oxide and water (moist silver oxide) use as a mild hydrolysing agent in organic chemistry in cases where aqueous caustic alkalis are too vigorous. Moist silver oxide, heated under reflux with an alkyl halide, will convert it to the corresponding alcohol.

2RI + Ag2O + H2O 2ROH + 2AgI

Decomposition of Silver oxide

Silver will oxidise slowly in the air if heated to 1000C-1200C. but the oxide decomposes again completely at 3000C.

4Ag + O2 2Ag2O

Silver Halide

Preparation of Silver halide compounds

Silver chloride, AgCl, Silver bromide, AgBr, and silver iodide, AgI, are all insoluble in water and precipitated by the addition of a solution of soluble chloride (NaCl), bromide (KBr) or iodide (KI) to a solution of silver nitrate. If required pure, all should protect fro sunlight, filtered off, washed with hot, distilled water and dried at about 1200C.

According to Sidgwick, the chloride and bromide are electrovalent compounds and the iodide mixed, electrovalent and covalent.

Cl + Ag+ → AgCl↓

I + Ag+ → AgI ↓

Ag++ Br → AgBr ↓

Properties of Silver halide compounds

These compounds show a typical halogen gradation in the properties summarised in the table below.

Properties of Silver halide
Silver halides

Properties of Silver Chloride compound

Silver chloride
Silver chloride

Silver chloride compound is readily soluble in aqueous solutions of ammonia, potassium cyanide and sodium thiosulfate. In all these cases, complex ions form (as below) which reduce the concentration of the Ag+ ion to a pint at which the solubility product of silver chloride can no longer reach so that it remains precipitated.

Ag+ + 2NH4OH [Ag(NH3)2] + 2H2O

Ag+ + 2CN Ag(CN)2

2Ag+ + 3S2O32- Ag2(S2O3)4-

Silver chloride can reduce to metallic silver in several ways, such as,

01.Heating in a current of dry hydrogen

2AgCl + H2 → 2Ag + 2HCl

02.Fusion with sodium carbonate or potassium carbonate

4Ag+ + 2CO32- 4Ag + 2CO2 + O2

The soluble matter then extracted by hot water. The silver filtered out, washed well by hot water and dried.

Uses of Silver halide compounds

Silver chloride uses in making printing out papers in photography. Silver bromide uses in making the light-sensitive emulsion fro photographic plates, films and gaslight papers.

Silver halide in photography
Silver halide in photography

Silver Fluoride – AgF

This handle is markedly different from the three considered above by being readily soluble in water. It makes by dissolving silver oxide in hydrofluoric acid and evaporating at very low pressure. Crystals of the hydrate, AgF.H2O, obtained.

Silver Nitrate

Preparation of Silver nitrate compound

Silver nitrate compounds made by dissolving silver with heat in moderately concentrated nitric acid. The main reaction is,

3Ag + 4H(NO3) 3AgNO3 + 2H2O + NO

Silver nitrate
Silver nitrate

Excess silver should be available to reduce the concentration of the remaining nitric acid to a very low value. After filtration, the liquid greatly reduces in bulk by evaporation. On cooling, which can filter, wash with caution (they are very soluble) and dry.

These crystals are exceptionally soluble in water.

The action of heat in Silver nitrate compounds

At 4500C, silver nitrate compounds decompose producing the nitrite.

2AgNO3 2AgNO2 + O2

At about 7000C, they decompose, leaving a bright, white mass of metallic silver, with the evolution of nitrogen dioxide and oxygen.

2AgNO3 2Ag + 2NO2 + O2

Uses of Silver nitrate

It melts at 2180C and can be cast into lunar caustic sticks, used in medicine as a cautery.

Also,

It uses in marking ink for linen. The organic matter reduces the nitrate to a very lasting black deposit of metallic silver.

Silver nitrate much use in the photographic industry in preparing the emulsions for plates.

Silver Carbonate – Ag2CO3

Silver carbonate

Silver carbonate is a pale yellow solid, precipitated by sodium carbonate solution from silver nitrate solution.

2Ag+ + CO32- Ag2CO3

Furthermore,

When heated as a dry solid, it decomposes. It leaves a bright, white deposit of metallic silver, liberating carbon dioxide and oxygen.

Ag2CO3 4Ag + 2CO2 + O2

Silver Sulfate compounds – Ag2SO4

Silver sulfate
Silver sulfate

This salt form when silver heat with concentrated sulphuric acid. But it is best made, as a precipitate, by mixing concentrated solutions of silver nitrate and sodium sulphate.

2Ag+ + SO42- Ag2SO4

It is sparingly soluble in water.

Silver Sulphide – Ag2S

Silver sulphide
Silver sulphide

This compound occurs as argentite. Apart from this, it is notable mainly as the cause of tarnishing of silver in an atmosphere containing traces of gaseous Sulphur compounds (SO2 or H2S). Silver sulphide can make by heating silver with Sulphur or hydrogen sulphide, or better, by precipitating it from silver nitrate solution by hydrogen sulphide.

Silver Cyanide – AgCN

When potassium cyanide solution add-in small amount to silver nitrate solution, a white precipitate of silver cyanide is thrown down.

Silver cyanide

Ag+ + CN AgCN

The addition of an excess of potassium cyanide solution causes the precipitate to dissolve by the formation of the complex silver cyanide ion.

AgCN + CN Ag(CN)2

Summary

Finally, From this article, we covered up all the compounds of silver and their properties and used as well.

Likewise, we have covered up the compounds of Strontium, Barium and Calcium as well.

Load More Related Articles
Load More By ScienceTute
Load More In Chemistry

Leave a Reply

Your email address will not be published. Required fields are marked *

Check Also

Preparation of Ethyl bromide

There are main 2 methods for the Preparation of Ethyl bromide. These two are the most suit…