Molecular Geometry

1. Molecular Geometry http://www.scl.ameslab.gov/MacMolPlt/Surface.JPG

2. A - central atom X -surrounding atom E -nonbonding valence electron-group integers VSEPR - Valence Shell Electron Pair Repulsion Theory • Each group of valence electrons around a central atom is located as far away as possible from the others in order to minimize repulsions. • The result is five electron-group arrangements of minimum energy seen in a large majority of molecules and polyatomic ions. • Because valence electrons can be bonding or nonbonding, the same electron-group arrangement can give rise to different molecular shapes. AXmEn Silberberg, Principles of Chemistry

3. linear tetrahedral trigonal planar trigonal bipyramidal octahedral Figure 10.3 Electron-group repulsions and the five basic molecular shapes. Silberberg, Principles of Chemistry

4. Figure 10.4 The single molecular shape of the linear electron-group arrangement. Examples: CS2, HCN, BeF2 Silberberg, Principles of Chemistry

5. Class Shape Figure 10.5 The two molecular shapes of the trigonal planar electron-group arrangement. Examples: SO2, O3, PbCl2, SnBr2 Examples: SO3, BF3, NO3-, CO32- Silberberg, Principles of Chemistry

6. The three molecular shapes of the tetrahedral electron-group arrangement. Figure 10.6 Examples: CH4, SiCl4, SO42-, ClO4- NH3 PF3 ClO3 H3O+ H2O OF2 SCl2 Silberberg, Principles of Chemistry

7. Figure 10.8 The four molecular shapes of the trigonal bipyramidal electron-group arrangement. PF5 AsF5 SOF4 SF4 XeO2F2 IF4+ IO2F2- XeF2 I3- IF2- ClF3 BrF3 Silberberg, Principles of Chemistry

8. Figure 10.9 The three molecular shapes of the octahedral electron-group arrangement. SF6 IOF5 BrF5 TeF5- XeOF4 XeF4 ICl4- Silberberg, Principles of Chemistry