Unit 3
Molecular Geometry
Molecular Geometry
• VSEPR (valence shell electron pair repulsion): all valence
electrons position themselves as far away as possible make specific shapes as a result
• Bond angle: angle formed between the center atom and
the bonded atom it is connected to
• Polar: unequal share of electrons between elements in a
compound - based on electronegativity - go towards the
most electronegative element
AX2
A
X
X
Linear
AX3
X
X
A
X
Trigonal Planar
AX2E
A
X
X
Bent
AX4
X
X
A
X
X
Tetrahedral
AX3E
X
A
X
X
Trigonal Pyramid
AX2E2
A
X
X
Bent
AX5
Trigonal Bipyramid
AX4E
Seesaw
AX3E2
T-shaped
AX2E3
Linear
AX6
Octahedral
AX5E
Square Pyramid
AX4E2
Square Planar
Macomber
Molecular Geometry Table
General Formula
Shape
Bond Angle
AX2
Linear
180
Hybridization
sp
AX3
AX2E
Trigonal Planar
Bent
120
<120
sp2
sp2
AX4
AX3E
AX2E2
Tetrahedral
Trigonal pyramid
Bent
109.5
<109.5
<109.5
sp3
sp3
sp3
AX5
AX4E
AX3E2
AX2E3
Trigonal bypyramid
Seesaw
T-shaped
Linear
90, 120
90, 120
90, 120
90, 120
sp3d
sp3d
sp3d
sp3d
AX6
AX5E
AX4E2
Octahedral
Square pyramid
Square planar
90
<90
<90
sp3d2
sp3d2
sp3d2
Steps
• Do out the Lewis structure using previous rules
• Determine the general formula (A = center, X =
connecting elements, E = electron pair around center)
• Record shape and bond angle using the chart provided
• Determine if the compound is polar or nonpolar (will
be polar if E’s around center or different elements
around center)
Examples
• Give the general formula, shape, bond
angle, and polarity of: H2O
Macomber
Molecular Geometry Table
General Formula
Shape
Bond Angle
AX2
Linear
180
Hybridization
sp
AX3
AX2E
Trigonal Planar
Bent
120
<120
sp2
sp2
AX4
AX3E
AX2E2
Tetrahedral
Trigonal pyramid
Bent
109.5
<109.5
<109.5
sp3
sp3
sp3
AX5
AX4E
AX3E2
AX2E3
Trigonal bypyramid
Seesaw
T-shaped
Linear
90, 120
90, 120
90, 120
90, 120
sp3d
sp3d
sp3d
sp3d
AX6
AX5E
AX4E2
Octahedral
Square pyramid
Square planar
90
<90
<90
sp3d2
sp3d2
sp3d2
Examples
• Give the general formula, shape, bond
angle, and polarity of: H2O
Examples
• Give the general formula, shape, bond
angle, and polarity of: CO2
Macomber
Molecular Geometry Table
General Formula
Shape
Bond Angle
AX2
Linear
180
Hybridization
sp
AX3
AX2E
Trigonal Planar
Bent
120
<120
sp2
sp2
AX4
AX3E
AX2E2
Tetrahedral
Trigonal pyramid
Bent
109.5
<109.5
<109.5
sp3
sp3
sp3
AX5
AX4E
AX3E2
AX2E3
Trigonal bypyramid
Seesaw
T-shaped
Linear
90, 120
90, 120
90, 120
90, 120
sp3d
sp3d
sp3d
sp3d
AX6
AX5E
AX4E2
Octahedral
Square pyramid
Square planar
90
<90
<90
sp3d2
sp3d2
sp3d2
Examples
• Give the general formula, shape, bond
angle, and polarity of: CO2
Examples
• Give the general formula, shape, bond
angle, and polarity of: BF3
Macomber
Molecular Geometry Table
General Formula
Shape
Bond Angle
AX2
Linear
180
Hybridization
sp
AX3
AX2E
Trigonal Planar
Bent
120
<120
sp2
sp2
AX4
AX3E
AX2E2
Tetrahedral
Trigonal pyramid
Bent
109.5
<109.5
<109.5
sp3
sp3
sp3
AX5
AX4E
AX3E2
AX2E3
Trigonal bypyramid
Seesaw
T-shaped
Linear
90, 120
90, 120
90, 120
90, 120
sp3d
sp3d
sp3d
sp3d
AX6
AX5E
AX4E2
Octahedral
Square pyramid
Square planar
90
<90
<90
sp3d2
sp3d2
sp3d2
Examples
• Give the general formula, shape, bond
angle, and polarity of: BF3