Answers to PS #1 - Classes at U. of L.

8. Draw the primitive unit cell for the body-centered cubic lattice.
9. As the body-centered tetragonal Bravais lattice is drawn in the notes (or Smart and Moore, Fig 1.24, p.23), it seems
that there are two sets of lattice points, one set at the body centers and another set at the corners of the parallelepiped.
Draw several adjacent unit cells and convince yourself that the two sets are equivalent. We can call either set the bodycenter
set and the other the corner set.
10. The cube and the regular octahedron (m3m) have the full symmetry of the cubic group, 48 symmetry elements.
Enumerate all 48 elements.
11. The tetrahedron ( 43m ) also is a member of the cubic class but contains only half the symmetry of the full cubic group.
Find the 24 symmetry elements of the tetrahedron.
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