Phase diagram earth metals

In each of the composition diagrams in Fig. 14.2, the numbers represent a series of reactions run at a defined composition and temperature. These are isometric sulfur slices through three-dimensional K/P/RE/S quaternary phase diagrams. As just one example of what we have studied. Table 14.1 identifies the compositions at each point and the resulting phase(s). We have rigorously studied how phase formation is dependent upon the compositions of reactions for the rare-earth elements Y, Eu, and La and we have also discovered key structural relationships between the rare-earth elements, indicating a significant dependence on rare-earth and alkali-metal size for sulfides and selenides. 

A detailed study of two rare-earth metals under one set of reaction conditions, for example, yielded the two composition phase diagrams, shown in Fig. 14.2, for the Fu and La thiophosphate systems [3]. To prepare these phase diagrams, we varied the alkah metal, the rare-earth metal, and the phosphorous concentration to kept the sulfur concentration constant We prepared similar studies in... 

Figure 4.17. The binary phase diagrams of the magnesium alloy systems with the divalent metals ytterbium and calcium (Ca is a typical alkaline earth metal and Yb one of the divalent lanthanides). Notice, for this pair of metals, the close similarity of their alloy systems with Mg. The compounds YbMg2 and CaMg2 are isostructural, hexagonal hP12-MgZn2 type.

The ZSA phase diagram and its variants provide a satisfactory description of the overall electronic structure of stoichiometric and ordered transition-metal compounds. Within the above description, the electronic properties of transition-metal oxides are primarily determined by the values of A, and t. There have been several electron spectroscopic (photoemission) investigations in order to estimate the interaction strengths. Valence-band as well as core-level spectra have been analysed for a large number of transition-metal and rare-earth compounds. Calculations of the spectra have been performed at different levels of complexity, but generally within an Anderson impurity Hamiltonian. In the case of metallic systems, the situation is complicated by the presence of a continuum of low-energy electron-hole excitations across the Fermi level. These play an important role in the case of the rare earths and their intermetallics. This effect is particularly important for the valence-band spectra. 

Fig. 13.3. The phase diagram of Ao.33A o.67Mn03 (A = divalent cation, A = rare earth) as a function of temperature and the global instability index of the idealized perovskite structure. The points show the observed transition temperatures in various compounds. FMM = ferromagnetic metal, PMI = paramagnetic insulator, FMI = ferromagnetic insulator (from Rao et al. 1998).

L. -L. Sun, F. Zhou, and Z.-X. Zhao, Superconductivity and phase diagram in iron-based arsenic-oxides RcFcAsOi r (Re = rare-earth metal) without fluorine doping, Europhys. Lett. 83 17002 (2008). 

Figure 7.20. Schematic diagram of the range of P chemical shifts in crystalline phosphate and aluminophosphate phases. The Q° range refers to the alkali and alkaline earth orthophosphates, Q denotes the end groups, the middle and ring groups and the branching groups in these compounds. The upper three bands refer to aluminophosphates, including those of the alkali and alkaline earth metals. From data of Turner et al. (1986a).

It has been shown that Na2 species form in the vapor phase. Describe the formation of the disodium molecule in terms of a molecular orbital energy-level diagram. Would you expect the alkaline earth metals to exhibit a similar property ... 

The change of halide ion results in weaker acidic properties for LnCl3 as compared with LnF3. This means that equilibrium (1.1.41) with the participation of alkali metal halide should be shifted to the left as compared with the fluoride complexes. That is, lithium chloride does not react with chlorides of the rare-earth elements with the formation of any compounds the binary phase diagrams are characterized by one simple eutectic. The same situation is observed for the binary diagrams for lithium- and rare-earth bromides. 

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