Carbon lattice

Refractory Compounds. Refractory compounds resemble oxides, carbides, nitrides, borides, and sulfides in that they have a very high melting point. In some cases, they form extensive defect stmctures, ie, they exist over a wide stoichiometric range. For example, in TiC, the C Ti ratio can vary from 0.5 to I.O, which demonstrates a wide range of vacant carbon lattice sites. 

Intercalation reactions (14.1) represent the ideal case there is an increase in the inter-layer distance while the carbon atom arrangement within the layers remains unchanged. However, during intercalation of cations from polymer [25] and solid [26] electrolytes, ternary phases (M (solv)yC /C (solv)yX ) are produced because the solvent from the electrolyte is also accepted into the carbon lattice. 

The carbon contents in fulvic and humic acids are 45-50% and 50-55%, respectively The carbon content shows broader variations because of the strong carbon lattice, the concentration of carbon is as high as 65%... 

The electronic structure of this tetragonal phase is semiconducting (Fig. 10b). Interestingly, the LDA fundamental gap value is 0.72 eV, being smaller than that of the fee C60. Introducing sp3 carbon into the originally sp2 carbon lattice does... 

Carbon materials, especially with low thermal history, usually include some impurities. Heteroatoms also can be considered as impurities. Importantly, many results have reported that heteroatoms can be introduced into the carbon lattice intentionally, which is defined as doping [52,53], Doping... 

Figure 15 Potential energy curves for two H atoms over a graphite surface, for the case where the target atom is initially chemisorbed, and the carbon lattice is allowed to relax for each configuration of the H atoms. Cases (a) and (b) correspond to the collinear and quasi-collinear configurations. The potential energy is plotted as a function of the distance of the incident H above the surface, for three positions of the target H 1.49 A (solid line, filled circles), 1.69 A (dashed line, open diamonds), and 1.89 A (dotted line, filled squares). The symbols correspond to the DFT calculations, and the lines correspond to the model PES. Taken from Ref. [90],...

Boron is one of the few elements which are known to be surely substituted to carbon into the carbon lattice. Having one electron less than carbon, boron in substitution can act as an electron acceptor and should be able to facihtate the insertion of electron donors [42, 49], such as lithium. This specific aspect of the nature of boronated carbons has attracted recently a particular attention with respect to the possible performance improvement of carbons used as anode material for rechargeable Li-ion batteries [40, 50]. 

Research has shown that the presence of catalytic surfaces and particles increases the yields and rates of formation of PCDD/F in combustion systems over the reaction temperature range of 200-600 °C. Transition metals such as copper can increase the rate of chlorination, molecular growth, and aromatic condensation reactions to form PCDD/F. Also, reactive species can attack a carbon matrix to chlorinate and fragment the carbon lattice-forming PCDD/F as well as other chlorinated hydrocarbons. Although research to date has focused on surface-me-... 

The electronic structure of nanotubes naturally influences their chemical behavior, too. Provided electrons close to the Fermi level are involved, the reactivity is expected to differ for all variants metalHc as well as semiconducting, either with small or with large bandgap. The exact position of the Fermi level, however, is largely dependent on the type and position of defects in the carbon lattice, so there is no simple correlation to be observed experimentally. Yet it has turned out in the course of time that certain reactions exhibit remarkable selectivity for specific types of nanotubes. These include, among others, the reaction with diazonium salts and the photochemical osmylation. 

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