It can be advantageous to choose a larger unit cell; in this case, a monoclinic cell twice the size
of the triclinic cell can be chosen:
If the lattice points are identified as the center of that six-membered ring, there is a lattice point
at the center of the C-face (defined by the a- and b- axes). The centering operation translates a
molecule by ½a + ½b.