Square pyramidal geometry describes the shape of certain chemical compounds with the formula ML5 where L is a ligand. If the ligand atoms were connected, the resulting shape would be that of a pyramid with a square base. The point group symmetry involved is of type C4v. The geometry is common for certain main group compounds that have a stereochemically-active lone pair, as described by VSEPR theory. Certain compounds crystallize in both the trigonal bipyramidal and the square pyramidal structures, notably [Ni(CN)5]3−.[1]
As a trigonal bipyramidal molecule undergoes Berry pseudorotation, it proceeds via an intermediary stage with the square pyramidal geometry. Thus even though the geometry is rarely seen as the ground state, it is accessed by a low energy distortion from a trigonal bipyramid.
Pseudorotation also occurs in square pyramidal molecules. Molecules with this geometry, as opposed to trigonal bipyramidal, exhibit heavier vibration. The mechanism used is similar to the Berry mechanism.
ExamplesEdit
Some molecular compounds that adopt square pyramidal geometry are XeOF4,[2] and various halogen pentafluorides (XF5, where X = Cl, Br, I).[3][4] Complexes of vanadium(IV), such as vanadyl acetylacetonate, [VO(acac)2], are square pyramidal (acac = acetylacetonate, the deprotonated anion of acetylacetone (2,4-pentanedione)).
square, pyramidal, molecular, geometry, square, pyramidal, geometry, describes, shape, certain, chemical, compounds, with, formula, where, ligand, ligand, atoms, were, connected, resulting, shape, would, that, pyramid, with, square, base, point, group, symmetr. Square pyramidal geometry describes the shape of certain chemical compounds with the formula ML5 where L is a ligand If the ligand atoms were connected the resulting shape would be that of a pyramid with a square base The point group symmetry involved is of type C4v The geometry is common for certain main group compounds that have a stereochemically active lone pair as described by VSEPR theory Certain compounds crystallize in both the trigonal bipyramidal and the square pyramidal structures notably Ni CN 5 3 1 Square pyramidal molecular geometryExamplesChlorine pentafluoride ClF5 MnCl2 5Point groupC4vCoordination number5Structure of xenon oxytetrafluoride an example of a molecule with the square pyramidal coordination geometry Contents 1 As a transition state in Berry pseudorotation 2 Examples 3 See also 4 References 5 External linksAs a transition state in Berry pseudorotation EditAs a trigonal bipyramidal molecule undergoes Berry pseudorotation it proceeds via an intermediary stage with the square pyramidal geometry Thus even though the geometry is rarely seen as the ground state it is accessed by a low energy distortion from a trigonal bipyramid Pseudorotation also occurs in square pyramidal molecules Molecules with this geometry as opposed to trigonal bipyramidal exhibit heavier vibration The mechanism used is similar to the Berry mechanism Examples EditSome molecular compounds that adopt square pyramidal geometry are XeOF4 2 and various halogen pentafluorides XF5 where X Cl Br I 3 4 Complexes of vanadium IV such as vanadyl acetylacetonate VO acac 2 are square pyramidal acac acetylacetonate the deprotonated anion of acetylacetone 2 4 pentanedione See also EditAXE method Square pyramid Hypervalent molecule Molecular geometryReferences Edit Spiro Thomas G Terzis Aristides Raymond Kenneth N 1970 Structure of Ni CN 3 5 Raman infrared and x ray crystallographic evidence Inorg Chem 9 11 2415 doi 10 1021 ic50093a006 Square Pyramidal Molecular Geometry VSEPR Archived from the original on 2009 11 02 Square Pyramidal Geometry Miessler G L Tarr D A 2004 Inorganic Chemistry 3rd ed Pearson Prentice Hall ISBN 0 13 035471 6 External links EditChem Chemistry Structures and 3D Molecules permanent dead link Indiana University Molecular Structure Center Interactive molecular examples for point groups Molecular Modeling Animated Trigonal Planar Visual nbsp This stereochemistry article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Square pyramidal molecular geometry amp oldid 1165708154, wikipedia, wiki, book, books, library,
