Pentagonal pyramidal geometry

In the solid state, the (T -Me5C5)Si cation in 25 TPFPB displayed only a weak interaction with the anionic part, featuring an almost ideal pentagonal-pyramidal geometry (Figure 2.1). 

In some instances a pentagonal pyramidal geometry has been detected, even though on these occasions the 0x0 ligand of another molecule may act as seventh ligand as a long axial bond . In the case of vanadium, the bisperoxovanadium imidazole monoanion 13 was synthesized by Crans and coworkers . 

The geometry about antimony in tris(diphenyldithiophosphinato)antimony(III) is pentagonal pyramidal (44) with the lone pair thought to be occupying one of the apical positions in a... 

This is a convenient, facile, and high-yield preparative route for quantitative preparation of the complexes above no special equipment is required. UI3(THF)4 crystallizes in a P2x/c space group. It is mononuclear with pentagonal-pyramidal coordination geometry around the central uranium atom. This compound is stable until 75°C, then THF molecules are removed by steps, forming UI3 at 162°C. Lewis base adducts of uranium tri-iodide, such as UI3(THF)4 above, are synthetically useful precursors for trivalent uranium chemistry (see Sec. 5.3.2) [360]. 

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