_RDC.Atom_isotope_number_1
| Description | The mass number for the chemical element defined by the tag '_Atom_type' or any of its related tags. |
| Details: | |
| Parent saveframe | RDCs |
| Data type | int |
| DB table | RDC |
| DB column | Atom_isotope_number_1 |
| DB type | INTEGER |
| NULL allowed | yes |