Al cluster superatoms as halogens in polyhalides and as alkaline earths in iodide salts

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 Al(13)l(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 Al-13(-) core. We also report the existence of another series, Al(14)l(x)(-), that exhibits stability for odd numbers of I atoms. This series can be described as consisting of an Al(14)l(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.