Can an Electron-Shell Closing Model Explain the Structure and Stability of Ligand-Stabilized Metal Clusters?

We investigated the structure and stability of several aluminum hydride complexes to understand the essence of "superatom chemistry" and to gain a right perspective on the ligand (L)-stabilized metal (M) clusters. We successfully interpret the structure and stability using molecular orbital analysis, which clearly shows the failure of an electron-shell closing model (or a superatom model) to explain it. The structure and stability of AlmHn are closely associated with the molecular orbital stabilization owing to the effective orbital overlap between Al-m (M-m) and nH (nL). The importance of retaining the electronic structural integrity of M-m in MmLn-within an electron-shell closing model-has been underestimated or even disregarded, and this has created the current controversies in the scientific community.