International
Tables for
Crystallography
Volume A
Space-group symmetry
Edited by M. I. Aroyo

International Tables for Crystallography (2016). Vol. A, ch. 3.1, p. 711

Figure 3.1.3.4 

P. M. de Wolffc
[Figure 3.1.3.4]
Figure 3.1.3.4

The effect of the special conditions. Border lines of type-I and type-II regions are drawn as heavy lines if included. The type-I region is cross-hatched; the type-II region is a mere line. A heavy border line of a region stops short of an end point if the latter is not included in the region to which the border belongs. a, b net centred orthogonal (elongated); special conditions (3.1.3.3e)[link], (3.1.3.5e)[link].