Table 1. Structural parameters of the correct structure (R) and 36 trial structural models of barbituric acid in space group P21/c with Z′ = 1.
The molecules were shifted or rotated with respect to the lattice vectors according to the values of \Delta m and \Delta\varphi, which signify the change relative to the correct structure applied to each of the three components of the fractional position (\Delta m = \Delta m_{x} = \Delta m_{y} = \Delta m_{z}) or the molecular orientation (\Delta\varphi = \Delta\varphi_{x} = \Delta\varphi_{y} = \Delta\varphi_{z}).
| Structural model | a (Å) | b (Å) | c (Å) | β (°) | \Delta m | \Delta\varphi (°) |
|---|---|---|---|---|---|---|
| R | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| A1 | 4.9346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| A5 | 5.3346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| A10 | 5.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| A15 | 6.3346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| A20 | 6.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| B1 | 4.8346 | 9.0153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| B5 | 4.8346 | 9.4153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| B10 | 4.8346 | 9.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| B15 | 4.8346 | 10.4153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| B20 | 4.8346 | 10.9153 | 12.4192 | 107.729 | 0.00 | 0.0 |
| C1 | 4.8346 | 8.9153 | 12.3192 | 107.729 | 0.00 | 0.0 |
| C5 | 4.8346 | 8.9153 | 11.9192 | 107.729 | 0.00 | 0.0 |
| C10 | 4.8346 | 8.9153 | 11.4192 | 107.729 | 0.00 | 0.0 |
| C15 | 4.8346 | 8.9153 | 10.9192 | 107.729 | 0.00 | 0.0 |
| C20 | 4.8346 | 8.9153 | 10.4192 | 107.729 | 0.00 | 0.0 |
| Beta1 | 4.8346 | 8.9153 | 12.4192 | 108.229 | 0.00 | 0.0 |
| Beta5 | 4.8346 | 8.9153 | 12.4192 | 110.229 | 0.00 | 0.0 |
| Beta10 | 4.8346 | 8.9153 | 12.4192 | 112.729 | 0.00 | 0.0 |
| Beta15 | 4.8346 | 8.9153 | 12.4192 | 115.229 | 0.00 | 0.0 |
| Beta20 | 4.8346 | 8.9153 | 12.4192 | 117.729 | 0.00 | 0.0 |
| P1 | 4.8346 | 8.9153 | 12.4192 | 107.729 | −0.03 | 0.0 |
| P2 | 4.8346 | 8.9153 | 12.4192 | 107.729 | −0.04 | 0.0 |
| P3 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.04 | 0.0 |
| P4 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.06 | 0.0 |
| P5 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.08 | 0.0 |
| O1 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | −10.0 |
| O2 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | −15.0 |
| O3 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 9.0 |
| O4 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 10.0 |
| O5 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.00 | 11.0 |
| PO1 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.02 | 2.0 |
| PO2 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.03 | 3.0 |
| PO3 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.04 | 4.0 |
| PO4 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.04 | 5.0 |
| PO5 | 4.8346 | 8.9153 | 12.4192 | 107.729 | 0.04 | 6.0 |
| W | 7.8346 | 11.9153 | 13.4192 | 117.729 | 0.08 | 10.0 |