Alkali metals thermodynamics

The last isomerization is remarkable in that the triple bond can shift through a long carbon chain to the terminus, where it is fixed as the (kinetically) stable acetylide. The reagent is a solution of potassium diami no-propyl amide in 1,3-di-aminopropane. In some cases alkali metal amides in liquid ammonia car also bring about "contra-thermodynamic" isomerizations the reactions are successful only if the triple bond is in the 2-position. 

This isomerization, which must proceed through a 1,2,3-trienylanine, is not "contra-thermodynamic", since with a catalytic amount of potassium tert.-butoxide the same result is obtained. Enyne ethers, H2C=CH-CsC-0R, undergo a similar conversion into HCeC-CH=CH-OR upon interaction with alkali metal amides in liquid NH3, followed by hydrolysis . Enyne sulphides, H2C=CH-CsC-SR, and the hydrocarbons H2C=CH-CsC-R (R = or phenyl) give only tars or polymeric products under... 

Roland W. Oshe, ed.. Handbook of Thermodynamic and Transport Properties of Alkali Metals, lUPAC, Blackwell Scientific Publications, Oxford, U.K., 1985. 

The modes of thermal decomposition of the halates and their complex oxidation-reduction chemistry reflect the interplay of both thermodynamic and kinetic factors. On the one hand, thermodynamically feasible reactions may be sluggish, whilst, on the other, traces of catalyst may radically alter the course of the reaction. In general, for a given cation, thermal stability decreases in the sequence iodate > chlorate > bromate, but the mode and ease of decomposition can be substantially modified. For example, alkali metal chlorates decompose by disproportionation when fused ... 

For all three halates (in the absence of disproportionation) the preferred mode of decomposition depends, again, on both thermodynamic and kinetic considerations. Oxide formation tends to be favoured by the presence of a strongly polarizing cation (e.g. magnesium, transition-metal and lanthanide halates), whereas halide formation is observed for alkali-metal, alkaline- earth and silver halates. 

Three conceptual steps can be discerned in the definition of the ionic structure of fluoride melts containing tantalum or niobium. Based on the very first thermodynamic calculations and melting diagram analysis, it was initially believed that the coordination numbers of tantalum and niobium, in a molten system containing alkali metal fluorides, increase up to 8. 

The organization of the Handbook of Battery Materials is simple, dividing between aqueous electrolyte batteries and alkali metal batteries and further in anodes, cathodes, electrolytes and separators. There are also three more general chapters about thermodynamics and mechanistics of electrode reactions, practical batteries and the global competition of primary and secondary batteries. 

Thermodynamic information has been obtained in different stages of graphite bisulfate (A5). The results have been interpreted in terms of a model previously applied to alkali-metal-graphite compounds. Part of... 

This reaction is a principal method of forming IIIB-transition-metal cr bonds. The formation of thermodynamically favored alkali-metal halides or related salts and acids HX enhances the easy formation of those bonds. A second possible interaction between anionic metal bases and group-IIIB halides is a simple acid-base relationship without elimination of halide anions. However examples of this are rare, and they have been described often for group-IIIB compounds without halogen ligands ( 6.5.3.2). 

The nonnuclear chemistry of Fr reduces to studies of coprecipitation in which Fr shows the behavior of the heavier alkali metal. Coprecipitation is followed by ion exchange to concentrate Fr Physical (mp, density, crystal parameters) and chemical (thermodynamics, solvation entropies) properties are theoretically derived or extrapolated from the trends exhibited by the other alkali metals. 

As reported in the previous section, the reduction of 6 with alkali metals in THF led to metal-metal bonded species.22 Suitable substrates can intercept the d2 [ j9-But-calix[4]-(0)4 W] fragment, preventing the formation of such dimers, which represent a thermodynamic sink. 22... 

Table 6.2. Thermodynamic data for complexation of alkali metal ions by cryptands in water (Lehn Sauvage, 1975 Kauffmann, Lehn Sauvage, 1976).

In general, the cryptands (213) show a stronger correlation between thermodynamic stability and match of the metal ion for the cavity. Thermodynamic data for complexation of the alkali metal ions with a number of cryptands is summarized in Table 6.2. The data for the smaller (less flexible) cryptands 2.1.1, 2.2.1, and 2.2.2 illustrate well the occurrence of peak selectivity. 

The kinetics and thermodynamics of complex formation in methanol for the interaction of cryptands 2.1.1,2.2.1 and 2.2.2 with the alkali metal... 

Figure 7.4 Thermodynamic data needed in evaluation of the enthalpy of formation of MX(s). (a) Lattice enthalpy of sodium halides (b) lattice enthalpy of alkali iodides (c) electron gain and dissociation enthalpies of halides (d) ionization and atomization enthalpies of alkali metals.

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