Square antiprismatic molecular geometry

In chemistry, the square antiprismatic molecular geometry describes the shape of compounds where eight atoms, groups of atoms, or ligands are arranged around a central atom, defining the vertices of a square antiprism.[1] This shape has D4d symmetry and is one of the three common shapes for octacoordinate transition metal complexes, along with the dodecahedron and the bicapped trigonal prism.[2][3]

Square antiprismatic molecular geometry
, ReF
Point groupD4d
Coordination number8
μ (Polarity)0

Like with other high coordination numbers, eight-coordinate compounds are often distorted from idealized geometries, as illustrated by the structure of Na3TaF8. In this case, with the small Na+ ions, lattice forces are strong. With the diatomic cation NO+, the lattice forces are weaker, such as in (NO)2XeF8, which crystallizes with a more idealized square antiprismatic geometry.



  1. D. L. Kepert (1978). "Aspects of the Stereochemistry of Eight-Coordination". Progress in Inorganic Chemistry. 24: 179–249. doi:10.1002/9780470166253.ch4.
  2. Jeremy K. Burdett; Roald Hoffmann; Robert C. Fay (1978). "Eight-Coordination". Inorganic Chemistry. 17 (9): 2553–2568. doi:10.1021/ic50187a041.
  3. Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
  4. Langer, V.; Smrčok, L.; Boča, M. (2010). "Redetermination of Na3TaF8". Acta Crystallographica Section C. 66: pi85–pi86. doi:10.1107/S0108270110030556.CS1 maint: uses authors parameter (link)
  5. Peterson, W.; Holloway, H.; Coyle, A.; Williams, M. (Sep 1971). "Antiprismatic Coordination about Xenon: the Structure of Nitrosonium Octafluoroxenate(VI)". Science. 173 (4003): 1238–1239. Bibcode:1971Sci...173.1238P. doi:10.1126/science.173.4003.1238. ISSN 0036-8075. PMID 17775218.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.