Pentagonal columns

FIGURE 8.6. The crystal stmcture of WO2.72 nanorods, showing the corner- and edge-sharing WOe octahedra that form pentagonal columns and hexagonal channels. Lrom Frey et al. 

Figure 7 The generation of pentagonal columns in the WO3 structure. Blocks of four octahedra, circled in (a), are rotated hy 90° in (h) to produce four pentagonal tunnels. F ilhng of these tunnels hy O-M-O chains produces pentagonal columns, two of which are shaded in (c)...

WO2.72 is not included in the homologous series of CS structures, because besides edge- and comer-sharing octahedra also pentagonal columns exist (as described imder tungsten bronzes). 

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. 

Fig. 47. Formation of Ice III (a) Second neighbor connections across puckered rings and boat raings positions of discarded H2O molecules (b) pentagon rings and channel in "a" direction (c) O j and Ojj lattice points sharing one and two 0—0 bonds respectively with three pentagons (d) Oj columns defining fourfold screw axis (from Ref., 4>)...

The framework contains chambers of two kinds the dodecahedral chambers of twenty water molecules, and somewhat larger chambers formed by twenty-four water molecules. Each of these larger chambers has two hexagonal faces and twelve pentagonal faces. A vertical column of them, with hexagonal faces shared, occupies the center foreground of the drawing. 

III). The second is an equiradial design, a regular pentagon with one centre point (table 5.8, column 3, and figure 5.5), and it is this one that was chosen. 

Table 1. Enumeration of C Fullerene Isomers in the Range n = 20 to 100 (first three columns), and Isolated-Pentagon Isomers in the Range n = 70 to 140 (last three columns)"...

FIG. 1 A foam column, pentagonal dodecahedral bubble, and the cross-section of a PB channel. 

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