ThH 5 : An Actinide‐Containing Superhalogen Molecule

Thorium and its compounds have been widely investigated as important nuclear materials. Previous research focused on the potential use of thorium hydrides, such as ThH 2 , ThH 4 , and Th 4 H 15 , as nuclear fuels. Here, we report studies of the anion, ThH 5 − , by anion photoelectron spectroscopy and computations. The resulting experimental and theoretical vertical detachment energies (VDE) for ThH 5 − are 4.09 eV and 4.11 eV, respectively. These values and the agreement between theory and experiment facilitated the characterization of the structure of the ThH 5 − anion and showed its neutral counterpart, ThH 5 to be a superhalogen. ThH 5 − , which exhibits a C 4v structure with five Th−H single bonds, possesses the largest known H/M ratio among the actinide elements, M. The adaptive natural density partitioning (AdNDP) method was used to further analyze the chemical bonding of ThH 5 − and to confirm the existence of five Th−H single bonds in the ThH 5 − molecular anion.