Metal-Metal Bonded Compounds of the Early Transition Metals

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Corbett 9510278 Synthetic explorations will be pursued for novel materials among the metal-rich halides and chalcogenides of the early transition metals and the physical characterization of these materials. The studies will feature the unique group of highly reduced compounds in which metal cluster and condensed cluster phases are stabilized by strongly bound, interstitial elements. The cluster hosts will include scandium, yttrium and the lanthanides, the halides will be chlorine, bromine and iodine, the chalcogenides sulfur, selenium and tellurium. The interstitials in halides will feature the transition metals. Further characterization of the apparently metallic lanthanides-based compounds and of the nature of their electronic and magnetic transitions will be emphasized together with searches for other phases showing unusual properties and new structures and bonding. Physical properties of interesting phases will be defined by crystal structure, conductivity, magnetic susceptibility, and photoelectron spectroscopic measurements and augmented by extended-Huckel (band) calculations. Particular emphasis will be given to the nature of the bonding and the physical properties and to new horizons in solid state chemistry. %%% The need for new materials is well recognized. The long range objectives of the present program are to expand the boundaries of what is possible in the solid state, to understand and conceptualize the results as to stability, structure, bonding and properties and, ultimately, to provide sufficient information and experience to allow some systemization and reasonable predictions. Several new and exciting directions are proposed. The new emphases include binary, ternary and quaternary (interstitial) compounds of lanthanum, an element that has been investigated very little but which appears to exhibit some distinctive and remarkable compounds ***