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

International Tables for Crystallography (2016). Vol. A, ch. 1.7, p. 136

Figure 1.7.2.2 

U. Müllerb
[Figure 1.7.2.2]
Figure 1.7.2.2

Group–subgroup relations (Bärnighausen tree) from the ReO3 type to two polymorphic forms of WO3. The superscript (2) after the space-group symbols states the origin choice. + and − in the images of high-temperature WO3 and α-WO3 indicate the direction of the z shifts of the W atoms from the octahedron centres. Structural data for WO3 are taken from Locherer et al. (1999[link]).