Lattice composition dependence

The lattice parameters showed considerable variation from one crystal to another with average values a 875 pm, c 506 pm this is now thought to arise from variable composition depending on the precise preparative conditions used. 

Based on the concept of mixed-framework lattices, we have reported a novel class of hybrid solids that were discovered via salt-inclusion synthesis [4—7]. These new compounds exhibit composite frameworks of covalent and ionic lattices made of transition-metal oxides and alkali and alkaline-earth metal halides, respectively [4]. It has been demonstrated that the covalent frameworks can be tailored by changing the size and concentration of the incorporated salt. The interaction at the interface of these two chemically dissimilar lattices varies depending upon the relative strength of covalent vs. ionic interaction of the corresponding components. In some cases, the weak interaction facilitates an easy... 

FIGURE1.27 Composition dependence of the apparent lattice conductivity, ag, grain- boundary conductivity, a and the total conductivity, at, for SmICe1 I02 l/2 measured at 300, 400, and 500°C [115].. 

In order to understand the kinetic mechanism of deformation of a composite, one needs to know a pertinent rule of mixtures that defines the compositional dependent relaxation time. Consider the lattices for binary mixtures which consist of the number of lattice sites... 

The stretching and bending modes of zeolite lattices have weak Raman cross sections, which makes measuring high quality Raman spectra difficult. Laser induced fluorescence is also a common problem with dehydrated zeolites, although this can be overcome with the Fourier transform technique. As with the corresponding infrared spectra, the frequencies of the Raman active lattice modes depend on both the local structure and the composition of the zeolite lattice. 

Figure 4 shows the compositional dependence of the lattice a parameter and maximum... 

The crystal lattice parameters observed for these copolymers by X-ray diffraction are found to be almost identical to those of the P(3HB) homopolymer. The degree of crystallinity determined from the X-ray diffraction decreases steeply from 60 to 23% as the 3HP content in the copolymers increases from 0 to 37 mol%. The trends of composition dependence of the thermal properties and the X-ray diffraction are very similar to those for P(3HB-co-4HB) but not to those for P(3HB-co-3HV), as already mentioned above. Thus, it is reasonable to assume that in the P(3HB-co-3HP) samples containing up to 37 mol% 3HP unit, the 3HB units exist in the crystalline as well as in the noncrystalline regions, while almost all of the 3HP units exist only in the latter. To further investigate this point, the NMR relaxation times have been measured for the films cast from a chloroform solution. 

The peculiar temperature and composition dependence of the valence of chemically collapsed phases of SmS was first observed in the system Sm1 xGdxS (55). Recently a phase diagram in the (x, T)-plane has been proposed for this system (41) as well as for CeTh alloys (44). When cooled below about 200 K the chemically collapsed phases of SmS show a dramatic lattice expansion, in some cases with explosive character (55) and disintegration of the crystal into a black powder. An example of this transition towards a more divalent state of Sm on cooling in SmAs 18 S 82 and Sm 81 Y19S is shown in Fig. 22 and 23, where we show the data of Poliak et al (63). The temperature dependent configurational mixing of Sm ions which is directly visualized in the XPS data is the source of the anomalous temperature dependence of the lattice constant. No detailed analysis of the dependence of the Sm 4/lineshape on temperature... 

The results of a study of the dependence of the structure of thin layers of (SnTe)i j,(PbSe) and (SnTe)i j,(PbTe)j, on the phase composition (0 < e < 1) have shown the existence of a continuous series of solid solutions with the rock-salt structure in both systems. The composition dependence of the crystal lattice parameters of the solutions was in accord with Vegard s law. 

The composition dependence of the lattice parameters of the a8 and o phases were presented by [1988Vasl, 2002Ham] and [1952Mar]. 

Fig. lb. Cr-Fe-V. The composition dependencies of lattice parameters of the a8 V jCri Jc2 solid solution Composition... 

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