Intergrowth bronze

Fig. 12. High-resolution electron micrograph of BijWO, intergrowth bronze. The dark circles between the W03 slabs represent bismuth atoms.

Very similar structures to these intergrowth bronzes have also been found in the Sn-W-0 system. Two analogous phases to those above, but with W03-like slabs 2... 

A second example of the intergrowth structure is tungsten bronze, M,. WO3 (M = H, Li, Na, K, Rb, Cs, Ca, Sr, Ba, In, Tl, Ge, Sn, Pb, Cu, Ag etc. nowadays many bronzes such as Ti, V, Mo are well known ), so named because its colour is similar to that of alloy bronze CuZn. It has been shown to have a kind of intergrowth structure in a limited composition (x) range. Generally, the stability of the structural types (hexagonal, tetragonal, and cubic) depends both on the ionic radius (rj and the composition (x) of M. For instance,... 

Fig. 2.94 Structure model deduced from Fig. 2.93. The arrows I show the rows of tunnels of hexagonal prisms. The structure can be regarded as the intergrowth of HTB and DRO, which was named intergrowth tungsten bronze (1TB) by Kihlborg and co-workers.

Fig. 11. Schematic drawing of (1,4), (1,5) and (1,6) intergrowth tungsten bronzes. Hexagonal tunnels of HTB strips separate the W03 slabs shown in polyhedral form (after Kihlborg [92]).

Intergrowth Tungsten Bronzes.—The alkali-metal tungsten bronzes are among... 

Figure 31 (a) Electron micrograph of a crystal of an intergrowth tungsten bronze phase in the K.WOa system. The structure consists of slabs of WOs-like structure five octahedra wide separated by strips of the hexagonal tungsten bronze type, (b) A drawing of the idealized structure of the crystal in (a)... 

These two previous series of compounds suggested that large cations forming bronze phases with WO3 would yield, at least over the part of the composition range near to WO3 itself, intergrowth type of structures. So far two further groups have been reported, in the Pb-W-O and Ba-W-0 systems. In the lead system a series of... 

Figure 35 Scanning electron micrograph showing the plate-like crystal morphology of the intergrowth type of bronzes Sn W03, PbxWOs, and SoxWOs. The crystal shown is of a sample of overall composition Pbo.oaWOa magnification x260...

Abbreviations P, perovskite T, tetragonal H, hexagonal I, intergrowth Is, single row of tunnels in parent WO3 matrix Id, double tunnels PC, pentagonal column bronzes related to tetragonal TB type. 

Intergrowth tungsten bronzes exist when hexagonal tungsten bronzes coherently intergrow with the parent WO3 stmcture (Figs. 4.14 and 4.15). 

FIGURE 4.14. Intergrowth tungsten bronze structure of the pyrochlore type (single tunnel) [4.30],... 

Fig. 3. Illustration of the effects of multiple scattering in an image of an intergrowth bismuth-tungsten oxide bronze, nominally Bio.iWOa. The simulated images shown correspond to thicknesses of 20a (near the crystal edge) and 60a respectively, with an underfocus of 1220a.

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