Solvo-base

Likewise, amphoteric behaviour can be observed. For example Zn(NH2)2 is insoluble in liquid NH3 (as is Zn(OH)2 in H2O), but it dissolves on addition of the solvo-base KNH2 due to the formation of K2[Zn(NH2)4] this in turn is decomposed by NH4+ salts (solvo-acids) with reprecipitation of the amide ... 

Despite this, they are good solvents for chloride-ion transfer reactions, and solvo-acid-solvo-base reactions (p. 827) can be followed conductimetri-cally, voltametrically or by use of coloured indicators. As expected from their constitution, the trihalides of As and Sb are only feeble electron-pair donors (p. 198) but they have marked acceptor properties, particularly towards halide ions (p. 564) and amines. 

Cady and Elsey gave the so-called solvent-system definitions, which depend on the mode of self-ionization of the particular solvent. Each solvent is considered as a parent of acids and bases. A solvo-acid is defined as a solute which increases the concentration of cations characteristic of the pure solvent and a solvo-base as a solute which increases that of the anions characteristic of the pure solvent ... 

In liquid ammoniai self-ionization solvo-acid solvo-base... 

Whenever these definitions are used the terms solvo-acid and solvo-base should be applied in order to distinguish from acids and bases in the sense of the theory by Bronsted. 

Jander has made use of the solvent-system conceptions, but preferred to use the term acid-analogon in the place of solvo-acid and base-analogon in the place of solvo-base to stress the analogy with the reactions in water. ... 

Triphenylchloromethane, which is known to ionize in acceptor solvents acts also as a solvo-base by donating chloride ions to the solvent molecules ... 

All soluble bromides of the alkali metals and alkaline earth metals behave as solvo-bases in the respective covalent bromide solvent systems under consideration. While in iodine bromide and in aluminium bromide only few and very weak solvo-acids have been found, various acceptor bromides react readily with bromides in solutions of arsenic(III) bromide and mercury(II) bromide. 

Bromides of the electropositive metals including T1+ are typical solvo-bases in molten mercuric bromide. Mercuric oxide also behaves as a solvo-base, since it produces bromide ions by reaction with solvent molecules, e.g. ... 

Ionic reactions between solvo-acids and solvo-bases may lead to insoluble products such as thallium sulphate formed from mercury(II) sulphate and thallium bromide in molten mercury(II) bromide. Similarly anhydrous copper(II) sulphate can be prepared by using a copper(II) halide. Perchlorates, nitrates and phosphates of many other elements can be prepared in a similar manner. By allowing mer-cury(II) oxide to react with the sulphate in mercury(II) bromide solution a red, insoluble product of composition (Hg0)2HgS04 is formed. Analogous compounds are formed from the sulphide, selenide and telluride of mercury in molten mercuric bromide. 

The alkali iodides are soluble in molten iodine to give conducting solutions typical for weak 1 1 electrolytes. Alkali iodides have been regarded as solvo-bases and iodine monohalides as solvo-acids. A conductometric titration of potassium iodide with iodine monobromide in molten iodine shows a significant break at a molar ratio KI IBr = 1 1, indicating the reaction ... 

The activities (or, approximately, concentrations) of the solvo-acid and solvo-base (solvent minus a proton) are linked through the autoprotolysis or ion-product constant ... 

Interaction of solvents of the first kind with adds or bases (solvolysis) results in formation of solvo-acid or solvo-base and solvated conju te base or acid, respectively ... 

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