VSPER Structures
Chapter 6
Section 5
Molecular Geometry
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Help to
determine the
properties of
molecules
Molecular
polarity- the
uneven
distribution of
molecular
charge
VSPER Theory
• “valence shell, electron pair repulsion”
• Repulsion between the sets of valence-
level electrons surrounding an atom
causes these sets to be orientated as far
apart as possible
Using VSPER Theory
• Step one- Draw
the Lewis Dot
structure for the
compound CBr
• Step two- Be
sure to arrange
the atoms so
they are the
farthest
distance apart
4
VSPER and Molecular Geometry
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Molecular Shape:
Linear
Atoms bonded to the
central atom: 2
Lone pair of
electrons: 0
Type of molecule: AB2
Example Formula:
Carbon Dioxide
VSPER and Molecular Geometry
Molecular Shape:
Bent
Atoms bonded to the
central atom: 2
Lone pairs of
electrons: 1
Type of Molecule:
AB2E
Example: Water
VSPER and Molecular
Geometry
 Molecular Shape:
Trigonalplanar
 Atoms bonded to
central atom: 3
 Lone Pairs of
electrons: 0
 Type of molecule:
AB3
 Example: AlCl3
VSPER and Molecular
Geometry
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Molecular Shape: Tetrahedral
Atoms bonded to central atom: 4
Lone Pairs of electrons: 0
Type of molecule: AB4
Example: CH4
VSPER and Molecular Geometry
Molecular Shape:
Trigonal-pyramidal
Atoms bonded to
central atom: 3
Lone Pairs of
electrons: 1
Type of molecule:
AB3E
Example:PH3
VSPER and Molecular Geometry
•
•
•
•
•
Molecular Shape: Trigonal-bipyramidal
Atoms bonded to central atom: 5
Lone Pairs of electrons: 0
Type of molecule: AB5
Example: NbBr5
VSPER and Molecular Geometry
 Molecular Shape:
Octahedral
 Atoms bonded to
central atom: 6
 Lone Pairs of
electrons: 0
 Type of molecule:
AB6
 Example: SF6