Table 1. Structural parameters of the oxygen sublattice of P21/c-SI.
| Symmetry | P21/c |
| Molecules/unit cell | 4 |
| a(Å) | 2.87 |
| b(Å) | 3.11 |
| c(Å) | 3.58 |
| β(°) | 151 |
| O position | 0.636, −0.077, 0.013 |
The structural parameters are calculated at 1.9 TPa and 1,600 K. a, b and c are the edges of the monoclinic unit cell. β is the angle between a and c. The position of one O atom in units of the cell parameters (a, b, c) is given in the last entry. The positions of the three other oxygens in the cell are obtained from the position in the table by symmetry operations.