Studies on the Hexagonal Tungsten Bronzes of Potassium, Rubidium, and Cesium.

On the origin of the spontaneous formation of nanocavities in hexagonal bronzes (W,V)O3

“…They could be assigned directly to the hexagonal phase NaxWO3+x/2.zH2O, 17 P63/mcm, a= 0.7298 nm, c= 0.7798 nm. 18 Octahedra tilting in the HTB-type compounds always seem to be observed and it has been previously reported as related to the doubled periodicity along c. 19,20 By rotating around their edges, the tilts of neighboring octahedra are equal but opposite, thus being the origin of the c parameter doubling although it does not modify the periodicity along a.…”

Activation analysis with thermal and fission neutrons

“…The more commonly known tungsten bronzes are those of the alkali metals (40)(41)(42)(43)(44)(45) and rare earths (46), but bronzes have 2 also been reported for barium (47), uranium, copper (48), silver (49) and thai 1ium (50).…”

Synthesis and Characterization of Vanadium Substituted Potassium Tungsten Bronzes, K_xV_yW_1-yO₃

“…The potassium atoms occupy specific sites, the hexagonal tunnels. The homogeneity range of alkali metal K-, Rb-, and Cs-HTB phases were reported for 0.19 < x < 0.33 [6]. The lower stability limit greatly depends on the preparation conditions and can be extended up to x = 0.15 [1].…”

“…The crystal structure of tungsten bronzes [1,2] can be described as corner-sharing WO 6 octahedra, forming various kinds of tunnels where the metal atoms are located. Depending on the size, amount of the interstitial metal atom and synthesis temperature tungsten bronzes adopt four different structure types, namely, Perovskite Tungsten Bronzes (PTB) [3,4], Tetragonal Tungsten Bronzes (TTB) [5], Hexagonal Tungsten Bronzes (HTB) [6] and Intergrowth Tungsten Bronzes (ITB) [7]. Tungsten Bronze have interesting physical and chemical properties for which these materials are very demanding for modern technology [ 3 showing the degree of reduction of the bronzes depending on the value of x.…”