11. One form is rhombohedral and the other is hexagonal, the former having a disorder. 12. The geometry that the OSA finally chose is a rhombohedral lattice based on a cuboctahedron. 13. The Bravais lattices in the hexagonal crystal family can also be described by rhombohedral axes. 14. More complicated aggregations have also been observed, such as rhombohedral , tetragonal and orthorhombic phases. 15. The crystal system is a trigonal-rhombohedral class 3 and has space group of R. 16. Chabazite crystallizes in the triclinic crystal system with typically rhombohedral shaped crystals that are pseudo-cubic. 17. Under pressure scandium trifluoride also forms different crystal structures with rhombohedral , and above 3 GPa tetrahedral. 18. "' Eucryptite "'is a lithium bearing aluminium trigonal-rhombohedral crystal system. 19. Well known crystalline forms are ?-rhombohedral , ?-rhombohedral, and ?-tetragonal. 20. Well known crystalline forms are ?-rhombohedral, ?-rhombohedral , and ?-tetragonal.
