https://pubs.rsc.org/en/Content/ArticleLanding/2016/DT/C6DT00533K
Coordination complexes of niobium and tantalum pentahalides with a bulky NHC ligand - Dalton...
The 1 : 1 molar reactions of niobium and tantalum pentahalides with the monodentate NHC ligand 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (Ipr), in...