Lithium tungsten bronzes

The second group is the group of oxyfluorides that are derived from ferroelectric oxides by means of fluorine-oxygen substitution. The basic oxides are usually perovskite, tetragonal tungsten bronze, pyrochlore, lithium tantalate etc. [400]. 

Lithium Tungsten Bronze, LigWjOjj, obtained by fusion of lithium paratungstate with tin or by electrolysis of fused lithium paratungstate deep blue microscopic prisms. 

Lithium Potassium Tungsten Bronze, Li2W50j5.3K2W40i2, is... 

More recently, lithium tungsten bronzes have been studied as materials for reference electrodes (Gabel et al., 2004). 

L1XV2O5 is a non-stoichiometric compound (x 1) and acts as a Li atom store. When a small potential is applied across the cell, Li ions migrate from the lithium polymer electrolyte into the WO3 layer forming a tungsten bronze (see equation 22.42 and discussion). Its formation results in a colour change from colourless to blue. 

The author and Sokolova (193) investigated the catalysis of alcohols on tungsten bronzes, which possess a defective structure. An X-ray structural analysis was also made in this research. In spite of the defective structure, the catalytic activity of W-bronzes proved to be rather low, contrary to the electronic theory of catalysis. According to the latter, however, the catalytic activity decreases as bronzes are being reduced or lithium added, the detectivity decreasing too. From the BET data and the X-ray patterns it follows that the surface of bronzes is practically unaltered on reduction. On the other hand, the low activity... 

Protonic conduction is verified if hydrogen is evolved at the cathode in an electrolysis experiment with a hydrogen source at the anode. This has been used very elegantly by Kreuer, who used the blue colouring of tungsten bronzes when hydrogen is intercalated as a proof of proton conduction in lithium hydrazinium sulphate, HUAs and HUP. Several other workers have used the formation of hydrogen as a proof of proton conduction (Murphy (1964), Takahashi et al. (1976,1979) Chandra (1985)22 Iwahara et al. (1986) ). 

Raistrick ID, Mark AJ, Huggins RA (1981) Thermodynamics and Kinetics of the Electrochemical Insertion of Lithium into Tungsten Bronzes. Solid State Ionics, 5 351-354. doi 10.1016/0167-2738(81)90265-4... 

On the other side, there are efforts to use some bronzes as reference electrodes. Gabel et al. [191] who studied the behavior of several polycrystalline bronzes found that tungsten substituted lithium molybdenum oxide bronzes with general formula A cMoi yW3,03 may be applied as materials for solid-state reference electrodes. They found that the potential of such electrodes does not change significantly with the change of pH, sodium ion concentration, and redox potential of a studied solution. 

I. D. Raistrick [1983] Lithium Insertion Reactions in Tungsten and Vanadium Oxide Bronzes, Solid State Ionics 9/10, 425 30. 

It is shown that the cathodic electrolysis products of melts based on sodium tungstate, in which molybde-num(VI) or tungsten(VI) oxides, lithium or sodium molybdate, tungstate, and carbonate are dissolved, are molybdenum, tungsten, their bronzes and carbides, and carbon. It is found that the phase composition of electrolysis products is determined by the concentration of carbonate in the melt. The conditions are determined for the deposition of galvanic coatings of molybdenum and tungsten carbides on different materials. 

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