Whirling crystal system

A whirling crystal system (to whorl , a radially symmetrical leaf arrangement) is understood to mean a crystal system in which exactly one axis of rotation has a number greater than 2. This term is used to combine the trigonal , tetragonal and hexagonal crystal systems. In these crystal systems this marked axis is placed in the crystallographic c-direction.

According to Neumann's principle , all property tensors of the 2nd level in the whirling crystal systems have two different eigenvalues and a main axis in the c-direction. So are z. B. all crystals of these crystal systems optically uniaxial, that is, they are birefringent, and the optical axis lies in the direction of the crystallographic c-axis.

literature

• Will Kleber , Hans-Joachim Bautsch , Joachim Bohm , Detlef Klimm: Introduction to crystallography . 19th edition. Oldenbourg Wissenschaftsverlag, 2010, ISBN 978-3-486-59075-3 .