The electronic structure of HfF5- and WF5-

► The electronic structure of HfF5- and WF5- is computed using ab initio methods. ► Hafnium fluorides are much more stable than the corresponding tungsten fluorides. ► The detachment energy is 8.8 eV for HfF5- and is only 3.9 eV for WF5-. ► It is possible to photodetach WF5- while leaving HfF5- unaffected. ► Photodetachment can be used to suppress interfering 182W in the detection of 182Hf.