Crystallographic Point-Group Symmetry

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The crystallographic point-group symmetry associated with each space group is given on the top line of the space-group diagrams. There are 32 crystallographic point groups and these are shown in the table below:

Triclinic 1* -1          
Monoclinic 2* m* 2/m        
Orthorhombic 222 mm2* mmm        
Tetragonal 4* -4 4/m 422 4mm* -42m 4/mmm
Trigonal 3* -3 32 3m* -3m    
Hexagonal 6* -6 6/m 622 6mm* -62m 6/mmm
Cubic 23 m-3 432 -43m m-3m    

The 11 centrosymmetric point groups are shown in red, the 11 enantiomorphic point groups are shown in green, and the 10 polar point groups are shown with an asterisk *. (Note that in the above table, inversion axes are written with a minus sign in front of the axis symbol.)

The symbols for point groups -42m, 32, 3m, -3m, and -62m may be written in alternative forms so as to indicate symmetry with respect to the unit-cell axes, e.g. -42m, 321, and -31m.

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