Computational Chemistry

H

H

H

H

O

O O

O

H H

H H

H H

H H

H H H 2 C C CH 2

H

H

H

H C

H H

buckminsterfullerene, C 60

The bonds are of two kinds,

with lengths ca. 1.39 and 1.46Å

F

CF

ooh

D2d As for D 2 (above), plus two dihedral mirror

planes: the two planes that contain the HCH groups

bisect the two axes that are shown as dashed lines

(the third axis passes through CCC).

Td

S

F

F

F

F

F

F

Oh

I

O O

H

F

O

H F

O

H

CO 2 H

HO 2 C

HO

OH

H

H

Ci Inversion center ( )

F

F

H

H H

B

O

H O O

H

CooV

H

C

N

N

H

H H

C 3 axis

C 2 axis

C 2 axis

H

F

Cl Br

C

C 1 No symmetry elements

Cs The three atoms lie in a plane

O O

H H

C 2 Twofold rotation axis

C

H

H H

H

pyramidane

C4v

D2h As for D 2 (above), plus a mirror plane

D 2 A C 2 axis perpendicular to the ring plane,

and two C 2 axes perpendicular to that axis

C2h C 2 axis (perpendicular to the

molecular plane) and a horizontal

mirror plane (the molecular plane)

C3h C 3 axis and horizontal

mirror plane

C3V C 3 axis and three

mirror planes

C2v C 2 axis and two mirror planes passing

through this axis, one the molecular plane, the

other at right angles to the molecular plane

H

Fig. 2.20 Examples of molecules with various symmetry elements (belonging to various point
groups)

2.6 Symmetry 37