Chemistry

IR and Raman spectroscopy


Point groups C.1, C.i, C.s

C.1

Hermann Mauguin symbol: 1

Molecules belonging to this group have other than identity e no symmetry. Many complex organic molecules belong to this group. Simple examples are 2-butanol or chlorofluoramine (HNClF.).

C.i

Hermann Mauguin symbol: 1¯

Molecules from this group also have identity e (which all molecules have) only one inversion center. Examples are meso-tartaric acid and 1,2-dibromo-1,2-dichloroethane (HClBrC-CBrClH). The inversion center is only given in Sch├Ânflies symbology if it is the only symmetry element of the molecule in question. Groups are an exception C.niif n is odd.

C.s

Hermann Mauguin symbol: m

To the group C.s belong to molecules that (besides identity e) have only one mirror plane. Examples are quinoline, HN3, HOCl, OSCl2. Molecules belonging to this group occur often.