Solid state chemistry of alkali-metal-indium systems: Synthesis, characterization and bonding of indium cluster phases*

The chemistry of clusters of post-transition main-group elements has been extended to group 3 elements, indium in particular. The bonding in the known "naked" cluster ions ;A hypoelectronic "naked" cluster In;Another, by far more frequently observed way of reducing the charge of a cluster is through a formation of exo bonds to other clusters or isolated indium atoms. Each exo bond reduces the charge of the cluster by one through oxidation of the otherwise lone pair on that vertex. First-of-a-kind clusters with more than 12 atoms have been achieved by utilizing this option. 8-, 12- and 16-bonded closo-In;Another surprise in indium chemistry came with the discovery that in presence of the right ingredients this element forms fullerene-type cages of different sizes, analogous to the well known carbon fullerenes. Fused cages of 70, 74 and 78 indium atoms contain isolated, Ni(Pd, Pt)-centered indium clusters at their centers. Spherical layers of sodium cations shield the inside surface of the cage from the indium atoms of the central cluster. The whole formation can be compared with an onion bulb with layers of In, Na, In and Ni inward from the surface. ftn*This work was performed at Ames Laboratory under contract no. W-7405-eng-82 with the U.S. Department of Energy. The United States government has assigned the DOE Report number IS-T 1648 to this thesis.