Themes > Science > Chemistry > Inorganic Chemistry > Chemical Bonding > VSEPR
VSEPR stands for valence shell electron pair repulsion. To determine the three dimensional VSEPR model, first you draw the Lewis Structure. Then using the same central atom, you place the electron pairs around the atom as far apart as possible from each other. Molecules with two or three electron pairs yield two-dimensional models. Four or more electron pairs yield three-dimensional VSEPR models. you can determine the name of the structure using the following diagrams.
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The first alignment is Linear, in which there are two regions of bonding on a central atom. each outer atom is 180 degrees apart. The linear arrangement has an orbital hybridization of "sp" |
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The second alignment is Trigonal Planar, because the three outer atoms form a triangle All in the same plane. In this form, all atoms are 120 degrees apart and have the orbital hybridization of "sp2" |
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The third alignment is Tetrahedral, in which there are four atoms equally spaced around a central atom. Each outer atom is 109.5 degrees apart and have the orbital hybridization of "sp3" |
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The fourth alignment is Trigonal Bipyramidal because the five outer atoms form two pyramids (one on top, the other upside down on the bottom) around the central atom. In this model, all atoms are 90 degrees or 120 degrees apart and have the orbital hybridization of "sp3d" |
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The final alignment is Octahedral, not because it has eight outer atoms, because it actually has six, but because it forms eight 90 degree angles. The orbital hybridization is "sp3d2" |
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