Solid-state reactions characteristics

These structural problems are also insoluble by physical methods alone. The infrared spectrum often gives an unambiguous decision about the structure in the solid state the characteristic bands of the carbonyl or the hydroxyl group decided whether the compound in question is a carbinolamine or an amino-aldehyde. However, tautomeric equilibria occur only in solution or in the liquid or gaseous states. Neither infrared nor ultraviolet spectroscopy are sufficiently sensitive to investigate equilibria in which the concentration of one of the isomers is very small but is still not negligible with respect to the chemical reaction. 

The stability of suspensions, emulsions, creams, and ointments is dealt with in other chapters. The unique characteristics of solid-state decomposition processes have been described in reviews by D. C. Monkhouse [79,80] and in the monograph on drug stability by J. T. Carstensen [81]. Baitalow et al. have applied an unconventional approach to the kinetic analysis of solid-state reactions [82], The recently published monograph on solid-state chemistry of drugs also treats this topic in great detail [83],... 

Solid state reactions are also very common in producing oxide materials and are based on thermal treatment of solid oxides, hydroxides and metal salts (carbonates, oxalates, nitrates, sulphates, acetates, etc.) which decompose and react forming target products and evolving gaseous products. Solid-state chemistry states that, like in the case of precipitation, powder characteristics depend on the speed of the nucleation of particles and their growth however, these processes in solids are much slower than in liquids. 

The characteristic melting points and IR frequencies of 55 indicate well-defined compounds. The second molecule HX in the salts d, d, e, e is probably firmly included, forming hydrogen bonds to the available oxygen atoms. These salts are easily obtained and should be versatile building blocks in solid-state reactions or reactions in dry aprotic solvents [9]. 

The amount and uniformity of the solid state reaction of halogen with TTF was probed by the electron microprobe technique. In this analytical method, low energy electron irradiation of a sample provides X-ray core level emissions, characteristic of the element and its relative concentration. Our initial analyses indicated a dramatic dependence of the halogen concentration with the energy of the electron beam. To probe this phenomenon further,... 

Heterogeneous solid state reactions occur when two phases, A and B, contact and react to form a different product phase C. A and B may be either chemical elements or compounds. We have already introduced this type of solid state reaction in Section 1.3.4. The rate law is parabolic if the reacting system is in local equilibrium and the growth geometry is linear. The characteristic feature of this type of reaction is the fact that the product C separates the reactants A and B and that growth of the product proceeds by transport of A and/or B through the product layer. 

Nuclei provide a large number of spectroscopic probes for the investigation of solid state reaction kinetics. At the same time these probes allow us to look into the atomic dynamics under in-situ conditions. However, the experimental and theoretical methods needed to obtain relevant results in chemical kinetics, and particularly in atomic dynamics, are rather laborious. Due to characteristic hyperfine interactions, nuclear spectroscopies can, in principle, identify atomic particles and furthermore distinguish between different SE s of the same chemical component on different lattice sites. In addition to the analytical aspect of these techniques, nuclear spectroscopy informs about the microscopic motion of the nuclear probes. In Table 16-2 the time windows for the different methods are outlined. 

Most chemical reactions and spectroscopic work are carried out in solution. However, recent investigations have shown great potential for solid-state chemistry. First, supramolecular systems consisting of more than one kind of molecule exhibit characteristics that are different from those of the individual molecules. We have recently reported inverted supramolecular chirality of bis(zinc octae-thylporphyrin), an enantiopure monoamine system in solution and in the solid phase [3]. Secondly, solid-state reactions occur more frequently than previously envisaged [4-7], and they may give products in high yield that are unobtainable by reaction in solution. They are kind to the environment because of their solvent-free nature and hence are currently attracting attention from the industrial sector as well. Compared with thermal or chemical reactions, photochemistry is particularly... 

The lithiated transition metal oxide LiVMoOe has been synthesized by solid state reaction. This is the first report of this compound to be studied as an anode material. The synthesized LiVMo06 powder has been studied by means of X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) spectroscopy. The electrochemical characteristics of the prepared electrodes assembled in coin cells were also investigated in terms of half-cell performance. It is observed that the cell exhibits three stages of discharge plateaus in the ranges 2.1-2.0 V, 0.6-0.5 V and 0.2-0.01 V, respectively. 

LiVMoOe was successfully synthesized using the conventional solid-state reaction method, and its chemical and physical properties were examined by several analytical methods. We have shown that LiVMoOe does not possess good structural characteristics for a lithium half cell (Li/LiVMoOe) as a cathode in non-aqueous electrolyte environment. Furthermore, we suggest that LiVMoOe may instead be considered as an anode material of choice for developing rechargeable lithium-ion battery technology. 

The possibility of covalent interfullerene bond formation in solid and in some of its salts, results in a variety of dimers and polymers. Both the dimerization and the polymerization of Cgo are characteristic solid state reactions, up to now, neither of them were carried out in solution. In the fee lattice of C g the concentration of the reacting molecules is about 3 orders of magnitude higher than that in solution. The free rotation of the molecules allows for the geometrical conditions required by the transition state of the polymerization and the rigid polymer rods or sheets can form by a small rearrangement of the precursor structure. 

Most solid-state reactions investigated up to the late 1960s were observed mainly by accident, without design, a major difficulty being the absence of a general method for producing crystals that have desired characteristics. 

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