International
Tables for Crystallography Volume E Subperiodic groups Edited by V. Kopský and D. B. Litvin © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. E. ch. 1.2, p. 14
Section 1.2.8.2. Rod groups
a
Department of Physics, University of the South Pacific, Suva, Fiji, and Institute of Physics, The Academy of Sciences of the Czech Republic, Na Slovance 2, PO Box 24, 180 40 Prague 8, Czech Republic, and bDepartment of Physics, Penn State Berks Campus, The Pennsylvania State University, PO Box 7009, Reading, PA 19610-6009, USA |
For all rod groups, a limit is set on the z coordinate of the asymmetric unit by the inequalityFor each of the x and y coordinates, either there is no limit and nothing further is written, or there is the lower limit of zero.
For tetragonal, trigonal and hexagonal rod groups, additional limits are required to define the asymmetric unit. These limits are given by additional inequalities, such as and . Fig. 1.2.8.1 schematically shows the boundaries represented by such inequalities.