Conductive compounds

As in the case of Group IVA, combinations with these typical non-metals will not be treated in detail insofar as nitrogen compounds are concerned. Of interest with respect to this review are the highly conducting compounds that are obtained by the room-temperature reaction of tetrasulfur tetranitride with halogens, e.g., (SNBrg4)j. (1, 366,423). 

In semi-conducting compounds, we know that some of the electrons form bonds between the cation and the anion, either as covalent or ionic bonds (or somewhere in between). What happens to the rest Do they remeun around the parent atom Why are some solids conductive while others are not The following discussion addresses these questions. Obviously, we cannot be exhaustive but we can examine the main features of each phenomenon to show what happens in the solid. We will not derive the equations associated with each subject. This aspect is left to more advanced studies. 

Surface bleeding and migration into other adjacent non-conductive compounds can be a problem with some antistatic plasticisers. Migration of plasticiser to bonding agent interfaces can also be the cause of product failures during service life. 

Fig. 8.11 Partial lithium ion conductivity of the predominantly electronically conducting compound Lij+jSb as a function of stoichiometry. The variation in the conductivity is due to changes of the transport mechanism.

Some researchers investigated multiphase additives. Kojima et al. [101] ball-milled MgHj with a nano-Ni/Al Oj/C composite catalyst. The mixture decomposed at a really low temperature of 200°C but in vacuum. A complex composite catalyst BCN/Ni/Pd/SWNT (where BCN is barium-calcium niobium high-temperature proton conducting compound and SWNT is single-wall-nanotubes) was also used by Yoo et al. [102] high-temperature proton conducting for ball-milled MgH. It desorbed 3 wt.%H2 in about 3,600 s at 230-250°C in vacuum. 

Silver(I) halide complexes of oA could not be prepared. The phosphine ap, however, reacts with silver iodide to give a colourless, unstable, non-conducting compound of empirical formula Agl(ap). This compound reacts with excess ap to give the stable 2 1 adduct Agl(ap)2- Silver bromide and silver chloride react directly with the ligand to give similar 2 1 adducts. These complexes are essentially monomeric, contain three-coordinate silver (I) and uncoordinated olefinic groups. The structure of the 1 1 adduct is unknown. 

Glazov and Vigdorovich (1969) proceeded from the findings of Kurnakov and Zhemchuzhnyi (1908), which were consistent with the law of Vegard laid down later in 1917. They established on the basis of a number of examples a full linear dependence of hardness variation in metals and semi-conducting compounds (as solid solutions) on variation in chemical composition. 

Such models do not seem to explain the high specific conductivity observed in electronically conducting compounds. In an alkali metal, there is one conducting electron per atom. If some electronically conducting polymers are to conduct to within 1 or even 10% of this, it would seem to require 0.01 or 0.1 conductivity electrons per atom, and that is difficult to visualize as a consequence of surface adsorption of ions, which will seldom exceed 0 = 0.1 for surface occupancy. The mechanism by which such adsorption stimulates conductance inside the fibers has not yet appeared in understandable form. 

Among the several fields in which electronically conducting polymers are useful or may be so the future, are electrocatalysis, prosthetics, and electrodes suited for use with biomaterials, (d) Consider each of these areas and state the reasons you think electronically conducting compounds (those now available and those that may be synthesized) would have characteristic properties of special use in the areas mentioned. (Bockris)... 

Classification of Anhydrous Metal Halides. The metal halides vary in their properties from the ionic, high-melting, conducting compounds, such as sodium chloride, to the covalent, volatile, nonconducting compounds, such as osmium oetafluoride (m.p., 35°). The variations observed admit of some systematization by classification based on the oxidation state of the metal in the compound. 

The coupling of aryl halides with active methylene compounds, such as mal-onitriles and cyanoacetates, is of increasing interest due to its inherent difficulty and the interest of the resulting products as synthetic intermediates in the preparation of bio active [36,37], heterocyclic [38,39] or conducting compounds [40]. Bulky NHCs have been found to be excellent ligands in the coupling of aryl halides with malonitrile [41] in hot pyridine using NaH as base (Scheme 7). 

Design Rules for Crystalline Organic Metals and Superconductors. Several semiempirical rules [23-26], summarized in five requirements, may help to find new high-conductivity compounds and superconductors ... 

In this chapter we give a broad overview of the field of organic conductors, discussing in a general way the key issues that distinguish these from the more conventional conductive compounds. In later chapters, each topic is treated in greater detail by experts in these areas. Our effort will be to paint a broader picture and to attempt to show how the study of these systems fits with the rest of condensed-matter physics. 

Molecules and ions can penetrate between the layers of graphite to form interstitial or lamellar compounds. These so-called intercalation compounds are of two types, namely, nonconducting compounds, in which the planarity of the graphite layers is destroyed, and conducting compounds, in which the planarity of the graphite layers is preserved (see Intercalation Chemistry) ... 

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