VSEPR+Theory

The VSEPR (Valence Shell Electron-Pair Repulsion) theory states that electron domains will arrange themselves in an optimum geometry to minimize repulsion between them and the other negatively charged electrons domains. An electron domain is any place that electron resides, they can be non-bonded electrons, a single bond, a double bond, and so on. Linear has 2 Electron Domains Trigonal-planar has 3 Tetrahedral has 4 Trigonal-bipyramidal has 5 There is a fifth form called Octahedral which has 6 electron domains. Molecular Geometry depicts where the actual atoms are in the molecule, not the electrons. It may be the same as the Electron Geometry, but it might not be. For example water has a tetrahedral electron geometry, the electrons spaced themselves out. Two of those 4 regions consist of unbonded electrons, these do not appear in the Molecular Geometry because they are not actual atoms. One final thing is the estimated bond angle can be somewhat smaller when there are unbonded electrons present. They have a tendency to hang a little "looser" then bonded electrons, so they push the bond(s) closer together. Using water as an example again it at first glance seems to have a measure of 109.5 degrees, but in reality has a measure or approximately 105 degrees. Sources: Picture: http://www.uwec.edu/boulteje/chem103/LectureNotes/LectureNotes23_files/image009.jpg Info: __Chemistry: The Central Science__
 * VSEPR Theory**
 * Electron Domain Geometry**
 * Molecular Geometry**