Triangular prismane

Other problems, such as non-orientability, also contribute to making this a poor fix to a much deeper problem, especially for models whose geometry is not heuristically simple. See the discussion of triangular prismane vs. triangular Moebiane in [79]. 

Figure 7 shows the ORTEP drawing of the hexasilaprismane 1237. Its structural parameters are listed in Table 4. The crystal has a two-fold axis of symmetry. The skeleton has a slightly distorted prismane structure with two triangular units [Si-Si = 2.374-2.387 A (av. 2.380 A) and ZSi-Si-Si = 59.8-60.3° (av. 60.0°)] and three... 

The hexamer Ge6[CH(SiMe3)2]6 has a prismane structure as shown in Fig. 14.7.3(e). The Ge-Ge distances within the two triangular faces are 258 pm, being longer than those in the quadrilateral edges, which are 252 pm. On the other hand, the hexamer (SnPh2)6 exists in the chair conformation, (as shown in Fig. 14.7.3(f)) with Sn-Sn distances 277 to 278 pm. 

Table V gives structural parameters of prismanes (C, Si, Ge) together with calculated values. The E-E bond length of the three-membered unit is denoted by the symbol a and that linking the triangular unit is indicated as h. The calculations of C and Si prismanes predict shortening of the bond length of the three-membered unit (a) relative to that of the four-membered unit (h) (I6a,b). Indeed, unsubstituted prismane (43) and derivatives of the type CftR6 [R = Me (44) and R = SiMe (45)] are in accordance with this prediction. However, owing to steric repulsions the skeleton of Si6R6 (25 R = 2,6-/-Pr2CfiH3) (a = 2.374-2.387 A, h = 2.365-...

An interesting comparison is offered by the prismane molecule, a polycyclic hydrocarbon with formula whose carbon and hydrogen atoms are arranged in the shape of a six-atom triangular prism. The magnetic symmetry is the same as cyclopropane s D-jhiCih)- It is a valence isomer of benzene, far less stable than the archetypal aromatic molecule. A spatial ring current model for this molecule has been reported [115]. 

Ladenburg benzene An incorrect structure for BENZENE in which the six carbon atoms are at the corners of a triangular prism. It is named for Albert Ladenburg (1842-1911). The actual compound, known as prismane, was synthesized in 1973. 

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