Pentagonal bipyramids are claimed to be promising coordination geometries for lanthanide-based single-molecule magnets, since (a) they present no extradiagonalcrystal 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.[4]
^Roald. Hoffmann; Barbara F. Beier; Earl L. Muetterties; Angelo R. Rossi (1977). "Seven-coordination. A molecular orbital exploration of structure, stereochemistry, and reaction dynamics". Inorganic Chemistry. 16 (3): 511–522. doi:10.1021/ic50169a002.
^Zhenyang Lin; Ian Bytheway (1996). "Stereochemistry of Seven-Coordinate Main Group and d0 Transition Metal Molecules". Inorganic Chemistry. 35 (3): 594–603. doi:10.1021/ic950271o.