• Source: Pentagonal bipyramidal molecular geometry

In chemistry, a pentagonal bipyramid is a molecular geometry with one atom at the centre with seven ligands at the corners of a pentagonal bipyramid. A perfect pentagonal bipyramid belongs to the molecular point group D5h.
The pentagonal bipyramid is a case where bond angles surrounding an atom are not identical (see also trigonal bipyramidal molecular geometry). This is one of the three common shapes for heptacoordinate transition metal complexes, along with the capped octahedron and the capped trigonal prism.
Pentagonal bipyramids are claimed to be promising coordination geometries for lanthanide-based single-molecule magnets, since (a) they present no extradiagonal crystal field terms, therefore minimising spin mixing, and (b) all of their diagonal terms are in first approximation protected from low-energy vibrations, minimising vibronic coupling.




Examples


Iodine heptafluoride (IF7) with 7 bonding groups
Rhenium heptafluoride (ReF7)
Peroxo chromium(IV) complexes, e.g. [Cr(O2)2(NH3)3] where the peroxo groups occupy four of the planar positions.
ZrF3−7 and HfF3−7




References






External links


[1] – Images of IF7
3D Chem – Chemistry, Structures, and 3D Molecules
IUMSC – Indiana University Molecular Structure Center

Kata Kunci Pencarian:

• Pentagonal bipyramidal molecular geometry
• Trigonal bipyramidal molecular geometry
• Pentagonal bipyramid
• Molecular geometry
• Octahedral molecular geometry
• Deltahedron
• VSEPR theory
• Fluorine
• Molecular symmetry
• Bartell mechanism