Low symmetry point groups include the C1, Cs, and Ci groups
Group
Description
Example
C1
only the identity operation (E)
CHFClBr
Cs
only the identity operation (E) and one mirror plane
C2H2ClBr
Ci
only the identity operation (E) and a center of inversion (i)
C2H2Cl2Br
High Symmetry Point Groups
High symmetry point groups include the Td, Oh, Ih, C∞v, and D∞h groups. The table below describes their characteristic symmetry operations. The full set of symmetry operations included in the point group is described in the corresponding character table.
Group
Description
Example
C∞v
linear molecule with an infinite number of rotation axes and vertical mirror planes (σv)
HBr
D∞h
linear molecule with an infinite number of rotation axes, vertical mirror planes (σv), perpendicular C2 axes, a horizontal mirror plane (σh), and an inversion center (i)
CO2
Td
typically have tetrahedral geometry, with 4 C4 axes, 3 C2 axes, 3 S4 axes, and 6 dihedral mirror planes (σd)
CH4
Oh
typically have octahedral geometry, with 3 C4 axes, 4 C3 axes, and an inversion center (i) as characteristic symmetry operations
SF6
Ih
typically have an icosahedral structure, with 6 C5 axes as characteristic symmetry operations