Silver compounds Sodium ions

Sulfur Complexes. Silver compounds other than sulfide dissolve in excess thiosulfate. Stable silver complexes are also formed with thiourea. Except for the cyanide complexes, these sulfur complexes of silver are the most stable. In photography, solutions of sodium or ammonium thiosulfate fixers are used to solubilize silver hahdes present in processed photographic emulsions. When insoluble silver thiosulfate is dissolved in excess thiosulfate, various silver complexes form. At low thiosulfate concentrations, the principal silver species is Ag2(S203) 2j high thiosulfate concentrations, species such as Ag2(S203) 3 are present. Silver sulfide dissolves in alkaline sulfide solutions to form complex ions such as Ag(S 2 Ag(HS) 4. These ions are... 

A solid that contains cations and anions in balanced whole-number ratios is called an ionic compound. Sodium chloride, commonly known as table salt, is a simple example. Sodium chloride can form through the vigorous chemical reaction of elemental sodium and elemental chlorine. The appearance and composition of these substances are very different, as Figure 2-24 shows. Sodium is a soft, silver-colored metal that is an array of Na atoms packed closely together. Chlorine is a faintly yellow-green toxic gas made up of diatomic, neutral CI2 molecules. When these two elements react, they form colorless ciystals of NaCl that contain Na and Cl" ions in a 1 1 ratio. 

Because of the high values of conductivity which in individual cases are found at room temperature, such compounds are often called superionic conductors or ionic superconductors but these designations are unfounded, and a more correct designation is solid ionic conductors. Strictly unipolar conduction is typical for all solid ionic conductors in the silver double salts, conduction is due to silver ion migration, whereas in the sodium polyaluminates, conduction is due to sodium ion migration. 

D.ll Write formulas for the ionic compounds formed from (a) sodium and oxide ions (b) potassium and sulfate ions (c) silver and fluoride ions (d) zinc and nitrate ions (e) aluminum and sulfide ions. 

The properties of ionic compounds in solution are actually the properties of the individual ions themselves (Figure 9.1). These compounds are called strong electrolytes because their solutions conduct electricity well. For example, an aqueous solution of sodium chloride consists essentially of sodium ions and chloride ions in water. A similar solution of calcium chloride consists of calcium ions and chloride ions in water. If either solution is treated with a solution containing silver ions, the chloride ions will form silver chloride, which is insoluble. The chloride ions act independently of the cation that is also present, regardless of whether it is sodium ion, calcium ion, or any other ion. Because the properties of the compound are the properties of the component ions, we need to learn to write equations for only the ions that react, omitting the ions that remain unchanged throughout the reaction (Section 9.2). 

These are called precipitation reactions because they take place in water ( aqueous or aq ) solution and one compound is precipitated out of the solution (and can then be filtered, washed, recrystallised etc.). As with displacement reactions, some of the species present do not actually take any active part in the process (and so are called spectator ions). So in the first example, sodium chloride and silver nitrate are both soluble, so what is actually being mixed is a solution containing hydrated sodium ions and hyclrated chloride ions, with one containing hydrated silver ions and hydrated nitrate ions. The compound silver chloride has very low solubihty (the bonding between the ions is not readily broken down to allow hydration of the ions), so is precipitated from the solution ... 

Figure 11.42 shows the unit cell of sodium chloride. It has Cl ions at the corners as well as at the center of each cube face. Because the chloride ions are so much larger than the sodium ions, the CP ions are nearly touching and form an approximate cubic close-packed stracture of CP ions. The Na" ions are arranged in cavities of this close-packed structure. Some other compounds that crystallize in this stracture are potassium chloride, KCl calcium oxide, CaO and silver chloride, AgCl. 

If triphenylmethyl chloride in ether is treated with sodium, a yellow colour is produced due to the presence of the anionic spiecies PhsC". Alternatively, if triphenylmethyl chloride is treated with silver perchlorate in a solvent such as THF, the triphenylmethyl cation is obtained. More conveniently, triphenylmethyl salts, PhsC X", can be obtained as orange-red crystalline solids from the action of the appropriate strong acid on triphenylcarbinol in ethanoic or propanoic anhydride solution. The perchlorate, fluoroborate and hexafluoro-phosphate salts are most commonly used for hydride ion abstraction from organic compounds (e.g. cycloheptatriene gives tropylium salts). The salts are rather easily hydrolysed to triphenylcarbinol. 

However, the peroxomonophosphate ion decomposes relatively rapidly ia aqueous solution. A mixture of peroxodiphosphoric and peroxomonophoshoric acids can be produced by treatiag a cold phosphoric acid solution with elemental fluorine (qv) (49). Peroxodiphosphoric acid is not produced commercially. Ammonium, lithium, sodium, potassium, mbidium, cesium, barium, 2iac, lead, and silver salts have all been reported. The crystal stmctures of the ammonium, lithium, sodium, and potassium compounds, which crysta11i2e with varyiag numbers of water molecules, have been determined (50). 

Derbyshire and Waters202 carried out the first kinetic study, and showed that the chlorination of sodium toluene-m-sulphonate by hypochlorous acid at 21.5 °C was catalysed more strongly by sulphuric acid than by perchloric acid and that the rate was increased by addition of chloride ion. A more extensive examination by de la Mare et al.203 of the rate of chlorination of the more reactive compounds, anisole, phenol, and />-dimethoxybenzene by hypochlorous acid catalysed by perchloric acid, and with added silver perchlorate to suppress the formation of Cl2 and C120 (which would occur in the presence of Cl" and CIO-, respectively),... 

The tetraalkylammonium halides formed by complete alkylation of amines are ionic compounds that resemble alkali-metal salts. When silver oxide is used to precipitate the halide ion, tetraalkylammonium halides are converted to tetraalkylammonium hydroxides, which are strongly basic substances similar to sodium or potassium hydroxide ... 

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