  In this communication we analyze the stability, reactivity and possible
aromatic behavior of two recently reported clusters (Reveles J. U.; Khanna S.
N.; Roach P. J.; Castleman A. W. jr. Proc. Natl. Acad. Sci, 2006, 103, 18405),
viz., Al7C- and Al7O- in the light of the principles of the maximum hardness
and minimum electrophilicity as well as the nucleus independent chemical shift
values.
