Tungsten oxide Tunneling

A homologous series of cesium tungsten oxides having the formula Cs2 W4 iOi2 has been reported. The general stmcture consists of slabs composed of layers of the hexagonal tungsten bronze and the pyrochlore type. The alkali cations reside in between the layers and in the tunnels formed within the slabs. ... 

Monophosphate tungsten bronzes with pentagonal tunnels NASICON = Sodium super ionic conductor NLO = Nonlinear Optical PLZT = Lead lanthanum zirconium titanate PZT = Lead zirconium titanate SBT = Strontium Bismuth Tantalate, SrBi2Ta209 SOFC = Solid oxide fuel cell TTB = Tetragonal tungsten bronze YAG = Yttrium iron garnet 3D = Three-dimensional TEOS = Tetraethylorthosilicate. 

Alkali tungsten bronzes of the type M WOs, M = K, Rb, or Cs with 0.16 < x 0.3 may adopt the hexagonal tungsten bronze (HTB) stmcture in which the large Cs atoms reside in hexagonal tunnels formed by six WOe octahedra in 12-fold coordination. The limit of x, as determined by the stmcture is 1/3. The stmcture is of interest since these compounds display superconductivity with values between 1 and 7K. It is also found for several mixed oxides of Nb and Ta with large A cations. 

Tungsten-bronze Structure. This crystal structure is typified by certain alkali metal compounds of tungstic oxide. It is that of several niobate electroceramics. The structure is that of M06 groups (M=W,Ta,Ti,Nb etc) with spaces between, forming tunnels in the structure. These A-site tunnels are perpendicular to the c-plane, in which their section is surrounded by 3(A3) 4(A1) or 5(A2) oxygen atoms. Lower valency cations are located in these tunnels above and below... 

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