The highly energetic molecule Al4H6, with its distorted tetrahedral structure, was recently characterized via mass spectrometry and photoelectron spectroscopy investigations (Li, X.; et al. Science 2007, 315, 356). Here we present the preparation and structural investigation of the first analogous Al4R6 cluster compound. In order to understand the bonding in this kind of Al-4 molecule, density functional theory and second-order Moller-Plesset perturbation theory calculations were performed. The results obtained are discussed in comparison with bonding in other Al-4 moieties, especially the aromatic bonding behavior in the dianionic planar Al-4(2-) species (Li, X.; et al. Science 2001, 291, 859). Finally, on the basis of the results obtained for Al-4 species, a more general problem is discussed: the difference in bonding between Zintl ions and metalloid clusters.