Lithium oxide coordination number

Although much of the V NMR has been performed on model systems or catalytic materials containing vanadium, 29 >30 compounds such as V2O5 or VOPO4 are used in both the catalysis and lithium battery fields, and many of the results can be used to help elucidate the structures of vanadium-containing cathode materials. V NMR spectra are sensitive to changes in the vanadium coordination number and distortions of the vanadium local environments from regular tetrahedra or octahedra. >33 5>V isotropic chemical shifts of between —400 and —800 ppm are seen for vanadium oxides, and unfortunately, unlike... 

Silylamido groups are used throughout the periodic table to stabilize unusual types of bonding, coordination numbers and oxidation states. Lithium silylamides, generally prepared by reaction of the silylamine with alkyl- or aryllithium derivatives, play an important role in the synthesis of such molecules. 

Fluorite (CaF2) structure (Fig. 4-U)- Comparison of the fluorite structure (Fig. 4.14) with Fig. 4.12 shows that fluorite can be described as an fee array of Ca + with F ions in all the tetrahedral holes (forming a simple cubic sublattice of fluorides). In this case, the Ca " " and F sites are not interchangeable. This is to be expected, since we have twice as many F as Ca " " as noted earlier, there are indeed twice as many T-holes as lattice atoms. The coordination numbers of Ca + and F are eight and four, respectively. Other solids with this structure include the nuclear fuel U02-If we make the shaded spheres in Fig. 4.14 the cations, and the unshaded ones the anions, we have the antifluorite structure, which is typified by lithium oxide (an fee array of 0 - with Li+ in every T-hole). 

A Potassium has an ionic radius of 1.5 A compared with lithium at 0.9 A. This difference is reflected in their coordination numbers, where potassium is normally six- or eight-coordinate and lithium is often found to be four-coordinate. For example, lithium oxide forms the antifluorite structure with lithium in the tetrahedral holes ill a close-packed lattice of oxygen ions. 

When only one unit can be changed between the metal oxidation state, coordination number, and electron accounts, two metal atoms are required to form R-M species (Equation (2)). Equation (2) is also favorable for lithium metal, but the remaining alkali metals are limited due to the possibility of Wurtz coupling. 

Now we will overview some experiments that reveal the specificities of the Jahn-Teller effect in diluted crystals. First of all, we will discuss a justification of their relaxation origin. We have mentioned before that the first experiments were done on the crystals of aluminum oxide (corundum), yttrium aluminum garnet, yttrium iron garnet, and lithium gallium spinel doped with a number of 3d ions [10,11]. The main result was the discovery of attenuation maximum which was considered to be observed at cot 1 and reconstruction of the relaxation time temperature dependence. In some experiments reported later both the velocity and attenuation of ultrasound were measured as functions of the temperature. They were done on ZnSe and ZnTe crystals doped with transition metals. These crystals have the zinc-blende structure with the Jahn-Teller ion in tetrahedral coordination. The following... 

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