1. The SbO6 octahedra are corner- and edge-sharing.

2. The structure of the Alum crystals is regular octahedra which is a polyhedron having

3. These elongated “octahedra” are corner connected via the H2O molecule to form chains.

4. 8 The clays consist of silica tetrahedra and the octahedra contain magnesia surrounded by oxygen atoms and hydroxyl groups.

5. The considerable distortion of the coordination octahedra in the olivine lattice causes a broadening and splitting of the absorption bands.

6. The result is applied to calculate the integral Breadths of reflexions from crystals having the external forms of rectangular parallelepipeds, tetrahedra, octahedra and spheres

7. The crystal structure contains [AlO(h)6] and [SbO2O(h)4] octahedra as well as zigzag chains built up by [Cu(1)[4]O(h)4] and [Cu(2)[4+1]OO(h)4] polyhedra.

8. Biotites, where the "average" distortion ofthe octahedral layer decreases with increasing Fe content and the Ml site is more distorted and larger than the M2 site; (2) the reduction in (M-O) distance in the two octahedra causes a more marked reduction in the size of the