Background to Point Groups

Molecular Symmetry David J. Willock 2009 John Wiley Sons, Ltd. ISBN 978-0-470-85347-4 

C2 axis and two vertical mirror planes, ctv and ay. These molecules do not have any other rotation axes or mirror planes and do not have an inversion centre so, according to the operations met so far, this set completely describes the symmetry of both molecules. The two molecules are said to belong to the same symmetry point group because they have exactly the same set of valid symmetry operations. 

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