Example of bent electron arrangement (water molecule). Shows location of unpaired electrons, bonded atoms, and bond angles. The bond angle for water is 104.5°.
Valence shell electron pair repulsion (VSEPR) theory (/ˈvɛspər,vəˈsɛpər/VESP-ər,[1]: 410 və-SEP-ər[2]) is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.[3] It is also named the Gillespie-Nyholm theory after its two main developers, Ronald Gillespie and Ronald Nyholm.
The premise of VSEPR is that the valence electron pairs surrounding an atom tend to repel each other. The greater the repulsion, the higher in energy (less stable) the molecule is. Therefore, the VSEPR-predicted molecular geometry of a molecule is the one that has as little of this repulsion as possible. Gillespie has emphasized that the electron-electron repulsion due to the Pauli exclusion principle is more important in determining molecular geometry than the electrostatic repulsion.[4]
The insights of VSEPR theory are derived from topological analysis of the electron density of molecules. Such quantum chemical topology (QCT) methods include the electron localization function (ELF) and the quantum theory of atoms in molecules (AIM or QTAIM).[4][5]
^Cite error: The named reference Petrucci was invoked but never defined (see the help page).
^Stoker, H. Stephen (2009). General, Organic, and Biological Chemistry. Cengage Learning. p. 119. ISBN 978-0-547-15281-3.
^Jolly, W. L. (1984). Modern Inorganic Chemistry. McGraw-Hill. pp. 77–90. ISBN 978-0-07-032760-3.
^ abGillespie, R. J. (2008). "Fifty years of the VSEPR model". Coord. Chem. Rev. 252 (12–14): 1315–1327. doi:10.1016/j.ccr.2007.07.007.
^Bader, Richard F. W.; Gillespie, Ronald J.; MacDougall, Preston J. (1988). "A physical basis for the VSEPR model of molecular geometry". J. Am. Chem. Soc. 110 (22): 7329–7336. doi:10.1021/ja00230a009.
Valence shell electron pair repulsion (VSEPR) theory (/ˈvɛspər, vəˈsɛpər/ VESP-ər,: 410 və-SEP-ər) is a model used in chemistry to predict the geometry...
polarity of bonds. The octet rule and VSEPRtheory are examples. More sophisticated theories are valence bond theory, which includes orbital hybridization...
pair is a concept used in valence shell electron pair repulsion theory (VSEPRtheory) which explains the shapes of molecules. They are also referred to...
angles in the table below are ideal angles from the simple VSEPRtheory (pronounced "Vesper Theory")[citation needed], followed by the actual angle for the...
geometry are sometimes described as sp3 hybridized. The AXE method for VSEPRtheory states that the classification is AX3E1. The nitrogen in ammonia has...
and methylene (CH2). This geometry is almost always consistent with VSEPRtheory, which usually explains non-collinearity of atoms with a presence of...
above and below the plane (axial or apical positions). According to the VSEPRtheory of molecular geometry, an axial position is more crowded because an axial...
pentagonal bipyramidal structure, with D5h symmetry, as predicted by VSEPRtheory. The molecule can undergo a pseudorotational rearrangement called the...
gas compound xenon tetrafluoride adopts this structure as predicted by VSEPRtheory. The geometry is prevalent for transition metal complexes with d8 configuration...
approaches are used, including semi-empirical methods, density functional theory, Hartree-Fock calculations, quantum Monte Carlo methods, and coupled cluster...
molecule is linear with a bond length consistent with strong ionic bonding. VSEPRtheory would predict a bent shape similar to H 2O. Lithium oxide is used as...
1918 to the 1920s and from 1939 to 1945 Vespa Vespers (disambiguation) VSEPRtheory in chemistry, often pronounced "Vesper" This disambiguation page lists...
repulsion (VSEPR) theory, which can be used to predict molecular geometry based on empirical rules rather than on valence-bond or orbital theories. As the...
compounds that have a stereochemically-active lone pair, as described by VSEPRtheory. Certain compounds crystallize in both the trigonal bipyramidal and the...
this distortion is in pyramidal alkenes. AXE method Molecular geometry VSEPRtheory March, Jerry (1985). Advanced organic chemistry : reactions, mechanisms...
a non-bonded lone pair on the sulfur, so the structure predicted by VSEPRtheory is trigonal pyramidal, as in ammonia (NH3). In the hybrid resonance structure...
precursor to acid rain. The molecule SO3 is trigonal planar. As predicted by VSEPRtheory, its structure belongs to the D3h point group. The sulfur atom has an...
fourth apex of an approximately regular tetrahedron, as predicted by the VSEPRtheory. This orbital is not participating in covalent bonding; it is electron-rich...
qualitative theories. Such theories are easier to learn as they require little background in quantum theory. Within main group compounds, VSEPRtheory powerfully...
difluoride is a chemical compound with the formula OF2. As predicted by VSEPRtheory, the molecule adopts a bent molecular geometry. It is a strong oxidizer...
the crystal, the species adopts a pyramidal structure, in accord with VSEPRtheory. Bismuth chloride can be synthesized directly by passing chlorine over...
compounds, such as chloroform. Phosgene is a planar molecule as predicted by VSEPRtheory. The C=O distance is 1.18 Å, the C−Cl distance is 1.74 Å and the Cl−C−Cl...
described by a model that predicts the geometry of molecules known as VSEPRtheory. Examples of molecules with this structure include chlorine pentafluoride...
and lone pairs, in what has been called "a faithful visualization of VSEPRtheory in action". Another feature of the ELF is that it is invariant concerning...
stereochemistry is denoted in skeletal formulae. Solid-state chemistry VSEPRtheory Nuclear Overhauser effect Describes a method in nuclear magnetic resonance...
should feature the strongest bonding of all group 17 monofluorides. VSEPRtheory predicts a bent-T-shaped molecular geometry for the group 17 trifluorides...
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