Figure 3
Splitting of the cubic face form {123}cub (hexakisoctahedron, point group 4/m2/m, 48 faces) into four rhombohedral subforms (12 faces each) of point group 2/m with their rhombohedral axes along [111]cub and rhombohedral angle α = 90° (cf. Appendix B). (a) {123}rh (hexagonal dipyramid), (b) {23}rh (ditrigonal scalenohedron), (c) {13}rh (ditrigonal scalenohedron) and (d) {12}rh (dihexagonal prism), (e) combination of these forms yields the cubic hexakisoctahedron. [Note that the central distances of the faces are different for the four rhombohedral forms, but equal in the combination (e).] |