Pentagonal bipyramid molecular geometry



In chemistry a pentagonal bipyramid (or dipyramid) is a molecular geometry with one atom at the centre and 7 more at the corners of a pentagonal dipyramid. A perfect pentagonal bipyramid belongs to the molecular point group D5h. the pentagonal bipyramid is one of the only cases where bond angles surrounding an atom are not identical (see also Trigonal bipyramid molecular geometry), which is simply because there is no geometrical arrangement which can result in seven equally sized bond angles in three dimensions. There are other seven coordinate geometries, the mono-capped octahedron and mono-capped trigonal prism.

Examples
Iodine heptafluoride is a molecule with a pentagonal bipyramidal geometry.