MgO bulk
CRYSTAL
0 0 0
 225
4.21
2
 12 0.    0.    0.
  8 0.5   0.5   0.5
OPTGEOM
FULLOPTG
ENDOPT
END
12 3
1 0 3  2.  0.
1 1 3  8.  0.
1 1 3  2.  0.
8 2
1 0 3  2.  0.
1 1 3  6.  0.
99   0
END
SHRINK
8 8
END