Ichem point groups

C1

Apparently, no symmetry at all.
However, E and C 1 are present.
E = C 1 , hence C 1 not listed

Ci

E and σh are present

C2

E and C 2 are present.

C2v

E, (C n ) C 2 and (n σv) 2 σv are present.

C3v

E, (C n ) C 3 and (n σv) 3 σv are present.

C∞v

E, (C n ) C∞ and (n σv) an infinity σv, no σh plane Typical for linear molecules without a σh plane

C3h

E, (C n ) C 3 , σh and (Sn ) S3 (rotation and reflection) coinciding with (C n ) C 3

(S2n ): S4

E and (S2n ) S4 (implies C n )

Dnd: D4d

E, C4, (Cn), 4 C2 (n C2), and S8 (S2n)

D3h

E, C3, 3C2, sigmah, 3 sigmav

D∞h

E, C∞, an infinity of σv planes, a σh plane
Typical for linear molecules with a σh plane
i.e. “symmetrical” linear molecules

Td

-tetrahedron

Oh

-octahedron

In

-Icosahedron