RSS, Nov 2, 2011
VSEPR Practice Molecules and Ions
Here are forty-six molecules and ions that exhibit almost all the possibilities of molecular geometry, except for seven-coordinate structures. They are listed in order of numbers of electron domains - "regions of high electron density" - around the central atom(s). For the purposes of VSEPR a multiple bond is counted as a single "domain", a single bond is a "domain", and a lone pair (LP) is a "domain". There are several molecules of each basic geometry. In some molecules the preferred central atom is underlined if there might be an ambiguity in writing the Lewis structure. In this list only one molecule, C_{2}H_{2}, has two central atoms.
The five basic geometries of electron domains [ linear - trigonal
planar - tetrahedral - trigonal bipyramidal - octahedral ] are shown in
Table 9.1, p. 335, Brown&LeMay, 12th Edit. The thirteen possible molecular
geometries are shown in Tables 9.2, p. 337, and 9.3, p. 340.
2 domains - domain geometry is linear, 180° bond angle (sp hybridization)
CO_{2}, HCN, BeCl_{2}, C_{2}H_{2} |
3 domains - domain geometry is trigonal planar, 120° bond angles (sp^{2} hybridization)
NO_{3}^{-}, SO_{3}, BF_{3}, CO_{3}^{2-} |
SO_{2}, O_{3}, NO_{2}^{-}, PbCl_{2} |
4 domains - domain geometry is tetrahedral, 109.5° bond angles (sp^{3} hybridization)
CH_{4}, XeO_{4}, CCl_{4}, SiH_{4}, ClO_{4}^{-}, NH_{4}^{+} |
NH_{3}, PF_{3}, H_{3}O^{+}, XeO_{3}, ClO_{3}^{-} |
H_{2}O, OF_{2}, H_{2}S, SF_{2} |
5 domains - domain geometry is trigonal bipyramidal, 90°/120° bond angles (sp^{3}d hybridization)
PCl_{5}, SOF_{4}, AsF_{5} |
SF_{4}, IF_{4}^{+}, IO_{2}F_{2}^{-}, XeO_{2}F_{2} |
ClF_{3}, BrF_{3} |
XeF_{2}, I_{3}^{-}, IF_{2}^{-} |
6 domains - domain geometry is octahedral, 90° bond angles (sp^{3}d^{2} hybridization)
SF_{6}, IOF_{5} |
IF_{5}, TeF_{5}^{-}, XeOF_{4} |
XeF_{4}, ICl_{4}^{-} |
Here are the same forty-six molecules and ions in random order. Write the Lewis structure and determine the domain geometry for each. Then predict the molecular geometry and find it in the above table to check.
NO_{3}^{-}, TeF_{5}^{-}, SF_{4}, CO_{3}^{2-}, H_{2}S, PCl_{5}, BF_{3}, NH_{4}^{+}, AsF_{5}, HCN, XeO_{2}F_{2}, ClO_{4}^{-}, XeF_{4}, I_{3}^{-}, H_{3}O^{+}, ClF_{3}, SO_{2}, O_{3}, NO_{2}^{-}, XeOF_{4}, PF_{3}, SF_{6}, CH_{4}, XeF_{2}, XeO_{4}, SO_{3}, CCl_{4}, SiH_{4}, PbCl_{2}, NH_{3}, XeO_{3}, ClO_{3}^{-}, H_{2}O, OF_{2}, SF_{2}, CO_{2}, SOF_{4}, IF_{4}^{+}, IO_{2}F_{2}^{-}, BeCl_{2}, BrF_{3}, IF_{2}^{-}, IOF_{5}, IF_{5}, C_{2}H_{2}, ICl_{4}^{-} |
© 2011 by R. S. Strange