Other alkaline-metal halides

Rybkin and Seredenko reported the construction of empirical scales of oxoacidity (acidity rows) in molten KC1 at 800 °C and Csl at 650 °C [62, 63]. Estimation of the oxoacidic properties was performed for buffer solutions obtained by the addition of equimolar quantities of conjugated acid and base in the melt. E.m.f. (pO) measurements were performed in the potentiometric cell with the use of a membrane oxygen electrode Pt(02)lYSZ. 

In this work, the difference in acidity between the most acidic and the most basic solution was found to be 4.28 pO units. 

Homogeneous add-base equilibria and acidity scales in ionic melts 

the whole of this part of the book shows that the current state of investigations of homogeneous acid-base equilibria in high-temperature ionic solvents cannot be considered satisfactory. 

The correctness of the constants of the acid-base equilibria determined in molten alkali metal nitrates are doubtful, because the mentioned melts are referred to the solvents of the first kind for the oxoacidic reactions. This requires combining the titration of solutions of the solvent acid N02 with the 

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The auxiliary electrolyte is generally an alkali metal or an alkaline earth metal halide or a mixture of these. Such halides have high decomposition potentials, relatively low vapor pressures at the operating bath temperatures, good electrolytic conductivities, and high solubilities for metal salts, or in other words, for the functional component of the electrolyte that acts as the source of the metal in the electrolytic process. Between the alkali metal halides and the alkaline earth metal halides, the former are preferred because the latter are difficult to obtain in a pure anhydrous state. In situations where a metal oxide is used as the functional electrolyte, fluorides are preferable as auxiliary electrolytes because they have high solubilities for oxide compounds. The physical properties of some of the salts used as electrolytes are given in Table 6.17. 

Starting from the corresponding hydroxymethyl-benzocrown, it has been possible to generate the immobilized system (186) by reacting the above precursor with chloromethylated polystyrene (which is available commercially as Merrifield s resin). Typically, systems of this type contain a polystyrene matrix which has been cross-linked with approximately 1-4% p-divinylbenzene. In one study involving (186), a clean resolution of the alkali metal halides was achieved by HPLC using (186) as the solid phase and methanol as eluent (Blasius etal., 1980). In other studies, the divalent alkaline earths were also separated. 

Titanium metal also can be produced by electrolytic methods. In electrolysis, fused mixtures of titanium tetrachloride or lower chlorides with alkaline earth metal chlorides are electrolyzed to produce metal. Also, pure titanium can be prepared from electrolysis of titanium dioxide in a fused bath of calcium-, magnesium- or alkali metal fluorides. Other alkali or alkaline metal salts can be substituted for halides in these fused baths. Other titanium com-pouds that have been employed successfully in electrolytic titanium production include sodium fluotitanate and potassium fluotitanate. 

Rubidium metal alloys with the other alkali metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double halide salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and zinc. These complexes are generally water insoluble and not hygroscopic. The soluble rubidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide,... 

Additional factors complicating the matter arise from the chemical and thermal (in)stability of metal nanoparticles as well as from the proposed mobility of surface bound capping agents (usually thiols). The chemical stability or instability of thiol-capped metal nanoparticles towards oxidation (i.e., oxidation of surface-bound thiols in air or in the presence of other oxidants) [70], towards halides [71], and towards alkaline metal ions has been studied by a number of groups [72] using TEM, UV-vis, NMR, as well as X-ray photoelectron spectroscopy (XPS) [73], and this collective work highlights the importance of determining nanoparticle purity. 

The application of the Bom-Haber cycle to a theoretically determined lattice energy actually gives a value for A/f/ X" (g), or Ai / X(g) — E, and a knowledge of Aff/ X(g) is required before a value can be assigned to the electron aflSnity. Alternatively, if a value of the electron aflSnity is available from other sources a value for the enthalpy of formation of the free radical Afl/ X(g), can be obtained. However in some cases such as NO3, O2, NO2, X is not a free radical but a stable molecule whose enthalpy of formation is known and then the electron afiSnity can be found directly. In some other cases, for example, the alkali metal halides and the alkaline earth oxides, a bond... 

CHLOROMETHYL OXIRANE (106-89-8) C3H5CIO Highly flammable, polymerizable liquid. Forms explosive mixture with air [explosion limits in air (vol %) 3.8 to 21.0 flash point 69°F/21°C 88°F/31 °C autoignition temp 772 F/411 °C Fire Rating 3]. Reacts violently with water. Contact with elevated temperatures, contamination, strong acids, strong bases, metallic halides, aluminum, aluminum chloride iron(III) chloride and other chlorides of iron or zinc can cause explosive polymerization. Violent reaction with aniline, hypochlorite, isopropylamine, potassium ieri-butoxide (ignition), sulfuric acid. Mixtures with trichloroethylene forms explosive dichloroacetylene. Incompatible with aliphatic amines, alkaline earths, alkali... 

Pyridine is a tertiary amine its aqueous solution shows an alkaline reaction and precipitates the hydroxides of metals, some of which are soluble in an excess of the amine. Salts of pyridine like those of other amines form characteristic double salts with metallic halides. The ferrocyanide of pyridine and the addition-product of pyridine and mercuric chloride are difficultly soluble in water these compounds are used in the purification of the base. Pyridine is a very stable compound it can be heated with nitric acid or chromic acid without undergoing change but at 330° it is converted by a mixture of nitric acid and fuming sulphuric acid into nitropyridine, a colorless compound that melts at 41° and boils at 216°. At a high temperature pyridine is converted into a sulphonic acid by sulphuric acid. Chlorine and bromine form addition-products, e.g., C5H5N.CI2, at the ordinary temperature when these are heated to above 200°, substitution-products are formed. The hydroxyl derivative of pyridine is made by fusing the sulphonic acid with sodium hydroxide it resembles phenol in chemical properties. The three possible carboxyl derivatives of pyridine are known. The a-acid is called picolinic acid, the jS-acid nicotinic acid (664), and the 7-acid isonicotinic acid. 

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