Finding the point group of a molecule
Is it linear?	
	no
>	
Does it have	
six Cs	axes?
	no
	
Does it have	
three C4 axes?	
	no
	
Does it have	
four C	3 axes?
	no
	>
Does it have a	
rotation axis	
of order n > 2?	
yes
yes
Does it have n
C2 axes perpendicular to the C„ axis?
infinite groups
yes
icosahedral groups
yes
octahedral groups
yes
tetrahcdral groups
no
low-symmetry groups
yes
D groups
no
CandS groups
i.'
yes
. no
3Sd?
o?
4 no
yes
no
ves
no
yes
ves
no
ves
yes
| no
MOd? ■
ves
ves
no
\ no
I
no
S 9
ves
o
D.
D,.
C„
no
From fa)
(a)
N
Linear
Two or more C„n>2
N
N
11	N		
			
Goto (b)
©   @ ® @
Linear groups Cubic groups
(b>
N
Select Cn with highest n; then, is
|— oh?
N
N
Oh!
ncrd!
N
n<7v?
S2n?
©(g)©
Figure 3-15
Shriver, Atfcins. and Langford: INORGANIC CHEMISTRY, second edition ©1990, 1994 D. F. Shriver, P. W. Atkins, and C. H. Langford W. H. Freeman and Com pan y