The group
is one of the two groups of order 10. Unlike the cyclic
group
,
is non-Abelian. The molecule ruthenocene
belongs to the group
, where the letter
indicates invariance under a reflection of the fivefold axis
(Arfken 1985, p. 248).
has cycle
index given by
Its multiplication table is illustrated above.
The dihedral group
has conjugacy classes
,
,
, and
. It has 8 subgroups:
,
,
,
,
,
,
, and
, of which
,
, and
,
,
,
,
,
,
,
,
,
are normal.