Flow Chart - Point Group Determination

Molecular

Structure

Is the molecule

linear?

Does the

molecule contain

two or more unique

C

3

axes?

No

Does the

molecule contain an

inversion center?

Yes

D

!h

C

!v

Yes

No

Does the

molecule contain

two or more unique

C

5

axes?

Does the

molecule contain

two or more unique

C

4

axes?

No

Does the

molecule contain an

inversion center?

Yes

I

h

Yes

I

No

Does the

molecule contain an

inversion center?

O

h

O

Yes Yes

No

Does the molecule

contain one or more

reﬂection planes?

Does the

molecule contain an

inversion center?

T

h

Yes Yes

T

d

T

No

No

No

Does the

molecule contain a

proper rotation axis

(C

n

)?

No

Does the

molecule contain a

reﬂection plane?

Does the

molecule contain an

inversion center?

Identify the

highest order C

n

.

Are there n perpen-

dicular C

2

axes?

Does the

molecule contain a

horizontal reﬂection

plane ("

h

)?

Yes Yes

Does the

molecule contain n

dihedral reﬂection

planes ("

d

)?

D

nd

D

n

D

nh

Does the

molecule contain a

horizontal reﬂection

plane ("

h

)?

C

s

C

i

C

1

Does the

molecule contain n

vertical reﬂection

planes ("

v

)?

Does the

molecule contain a

2n-fold improper

rotation axis?

C

nh

C

nv

S

2n

C

n

No

No

Yes

Yes

Yes

No

No

Yes

Yes

No

No

Yes

Yes

No

No

No

Yes