| Allowed Value | Details | 
|---|---|
| constr | H-atom parameters constrained | 
| mixed | some constrained, some independent | 
| noref | no refinement of H-atom parameters | 
| refU | refined H-atom U's only | 
| refall | refined all H-atom parameters | 
| refxyz | refined H-atom coordinates only | 
| undef | H-atom parameters not defined | 
| Allowed Value | Details | 
|---|---|
| constr | H-atom parameters constrained | 
| mixed | some constrained, some independent | 
| noref | no refinement of H-atom parameters | 
| refU | refined H-atom U's only | 
| refall | refined all H-atom parameters | 
| refxyz | refined H-atom coordinates only | 
| undef | H-atom parameters not defined |