Experimental and theoretical characterization of aluminum-based binary superatoms of Al₁₂X and their cluster salts

The geometric and electronic structures of aluminum binary clusters, Al_nX (X = Si and P), have been investigated, using mass spectrometry, anion photoelectron spectroscopy, photoionization spectroscopy, and theoretical calculations. Both experimental and theoretical results show that Al ₁₂Si has a high ionization energy and low electron affinity and Al₁₂P has a low ionization energy, both with the icosahedral structure having a central Si or P atom, revealing that Al₁₂Si and Al₁₂P exhibit rare-gas-like and alkali superatoms, respectively. Experiments confirmed the possibility that the change in the total number of valence electrons on substitution could produce ionically bound binary superatom complexes, the binary cluster salts Al₁₂P⁺F^- and Al₁₂B^-Cs⁺.