Two classes of gas-phase aluminum-iodine clusters have been identified whose stability and reactivity can be understood in terms of the spherical shell jellium model. Experimental reactivity studies show that the Al13I-x clusters exhibit pronounced stability for even numbers of I atoms. Theoretical investigations reveal that the enhanced stability is associated with complementary pairs of I atoms occupying the on-top sites on the opposing Al atoms of the Al13- core. We also report the existence of another series, Al14I-x, that exhibits stability for odd numbers of I atoms. This series can be described as consisting of an Al14I-3 core upon which the I atoms occupy on-top locations around the Al atoms. The potential synthetic utility of superatom chemistry built upon these motifs is addressed.

Al13- is a cluster known for the pronounced stability that arises from coincident closures of its geometric and electronic shells. We present experimental evidence for a very stable cluster corresponding to Al13I-. Ab initio calculations show that the cluster features a structurally unperturbed Al13- core and a region of high charge density on the aluminum vertex opposite from the iodine atom. This ionically bound magic cluster can be understood by considering that Al13 has an electronic structure reminiscent of a halogen atom. Comparisons to polyhalides provide a sound explanation for our chemical observations.

Aluminum Aluminum I 2100Formation of Al 13 I -: Evidence for the Superhalogen Character of Al 13 . -Reactions of Al clusters with HI in a fast-flow tube apparatus lead to the formation of the very stable Al13Icluster. DFT calculations show that the cluster features a structurally unperturbed core and a region of high charge density on the Al vertex opposite from the iodine atom. This ionically bound magic cluster can be understood by considering that Al 13 has an electronic structure reminiscent of a halogen atom. -(BERGERON, D. E.; CASTLEMAN*, A. W.