Lithium tungstate

Kaltseis et al. [234] have investigated the recoil-free fraction of the 46.5 keV transition of W in anhydrous lithium tungstate. Their results can be expressed by an effective Debye temperature of 172 9 K which is in good agreement with a value of 205 40 K derived from X-ray diffraction measurements of Li2W04 powder. 

Lithium Tungstates.—The normal salt, solution when a suspension of tungstic anhydride in water is boiled with lithium carbonate, or when tungstic anhydride is added to fused lithium carbonate and the resulting mass extracted with water on evaporation, short, thick, oblique rhombic prisms separate, which readily dissolve in water yielding an alkaline solution. Lithium ditungstate is described by Anthon, but its existence is doubtfiil. 

The molar solution of lithium tungstate is obtained by dissolution of 8.4 g (0.2 mol) of lithium hydroxide and 23.2 g (0.1 mol) of tungsten(VI) oxide in 100 mL of hot water. The small amount of insoluble oxide is removed by nitration. 

Figure 6.25. Ionic conductivity of quenched lithium molybdate and lithium tungstate glasses. Samples were completely glassy except for 1 and 5, which were largely crystalline. (After Nassau ot al., 1980)...

Places where this map has a value close to the atomic valence are possible sites for the atom. Waltersson used the technique for locating Li atoms in lithium tungstates, but the technique can also be used for locating possible sites for defect atoms [27] and for plotting diffusion paths [13]. A variation of the valence sum map, the D map, calculated using Equation 10.3, identifies the cavities in a structure that can accommodate the diffusing or defect atom... 

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