Composition , analytical solid solutions

Questions of the analytic control of maintenance of the bivalent metals cations to their joint presence in materials of diverse fixing always were actual. A simultaneous presence in their composition of two cations with like descriptions makes analysis by sufficiently complicated process. Determination of composition still more complicates, if analyzed object is a solid solution, in which side by side with pair of cations (for example, Mg " -Co ", Mn -Co, Zn -Co ) attends diphosphate anion. Their analysis demands for individual approach to working of methods using to each concrete cations pair. 

In many cases, p is rather insensitive to the composition (NAO) because both A21 and B2+ are rendered mobile by the same vacancies in the same sublattice. In deriving Eqn. (8.11), we have assumed that (A, B)0 is an ideal quasi-binary solid solution. Analogous to Eqn. (8.6), Eqn. (8.11) has to be integrated under the restricting condition of the conservation of cation species A and B. There is no analytical solution to this problem, but a numerical solution has been presented in [H. Schmalzried, et al. (1979)]. 

The method of standard additions has been used to suppress the influence of the bulk composition of solid samples. It requires that the analyte contained in the solid sample and the added analyte be identically affected by the matrix. This method can be used in three different ways in connection with solid samples. One involves adding increasing amounts of analyte to fixed amounts of sample. In the second, a single amount of sample is subjected to a single addition of analyte from a standard solution, which can lead to inaccuracy in the final result. In the third approach, both the amount of solid sample used and that of standard added are varied the instrumental signal is a function of two independent variables and can be extracted by multiple linear regression. 

The catalyst was subjected to chemical anal3rsis, dissolution in a dilute solution of hydrochloric acid. X-ray diffraction analysis, and DTA. Inspection of these analytical data leads to the conclusion that the main constituent of this catalyst is an amorphous solid solution composed of metallic nickel and the nickel-phosphorus compound of formula Nii.gP, the overall composition of which is NirNii.sP = 2.7 1. 

Two general methods, the analytical method and the synthetic method (Grant and Brittain 1995), are available for determining solubility. In the analytical method, the temperature of equilibration is hxed, while the concentration of the solute in a saturated solution is determined at equilibrium by a suitable analytical procedure. The analytical method can be either the traditional, common batch agitation method, or the more recent flow column method. In the synthetic method, the composition of the solute-solvent system is hxed by appropriate addition and mixing of the solute and solvent, then the temperature at which the solid solute just dissolves or just crystallizes is carefully bracketed. 

An analysis of the experimental data was performed by consideration of the three binary systems water-NaCl, water-sucrose and NaCl-sucrose. Of these, the first system has been thoroughly studied, and the transition temperatures and compositions are included in Table 2. The situation is more complicated for water-sucrose mixtures, mainly because any crystallisation processes of sucrose or any of its hydrates from aqueous solutions are likely to be very slow, perhaps impossible to determine by DSC methods in real time. Some hydrates have, however, been identified by X-ray and chemical analytical methods they are also included in Table 2 and the (probable) equilibrium phase diagram is shown in Figure 8. As regards the anhydrous system NaCl-sucrose, no quantitative information exists. The crystallisation of NaCl from its solid solution in amorphous... 

The lattice parameters of the rare earth difluorides (fluorite structure, Fm3m, Z = 4) are listed in table 2 for the composition RF2.00- The analytical function a = mx -I-1 describes the relationships between the lattice parameter a and the chemical composition within the solid solutions RF, for 2.0Sx 2.2. This function is also a valid approximation for compositions with 2.2 < x 2.4 if the samples are quenched from 1200-1400 C. Attention, however, is called to partial ordering which can be seen in the X-ray diffraction patterns as broadening and... 

However, as will be shown below, the zero-order approximation model has a potentiality of direct analytical calculation of a larger part of phenomenologieal (fitting) model parameters of the next approximations. Calculation is performed on the basis of theoretical probabilistic analysis of the chemical compositions of unit cells of a solid solution crystal, which are possible in principle. Consideration of this fact should simplify and refine the theory of X-ray diffraction patterns. 

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