| Allowed Value | Details |
|---|---|
| D | distance or angle restraint on site |
| G | rigid-group refinement of site |
| P | partial occupancy constraint |
| R | riding-atom site attached to non-riding atom |
| S | special-position constraint on site |
| T | thermal displacement constraints |
| U | Uiso or Uij restraint (rigid bond) |
| Allowed Value | Details |
|---|---|
| D | distance or angle restraint on site |
| G | rigid-group refinement of site |
| P | partial occupancy constraint |
| R | riding-atom site attached to non-riding atom |
| S | special-position constraint on site |
| T | thermal displacement constraints |
| U | Uiso or Uij restraint (rigid bond) |