FORMATION AND STABILITY OF METALLOCARBOHEDRENES - TI(X)M(Y)C(12) (X+Y=8, M=NB, TA, Y, AND SI)

Binary element metallocarbohedrenes, Ti(x)M(y)C(12)(+) (M = Nb, Ta, Y, and Si, x + y = 8) are produced using a laser-induced plasma source. The experimental findings enable the assessment of the results of seve ral theoretical studies, providing indications of some shortcomings an d pointing out useful directions for future experimental work. Moreove r, the findings provide further insight into the mechanisms responsibl e for the formation of metallocarbohedrenes. They show that the format ion of sigma-bonds between metal atoms and C-2 units are the key to th e stability of metallocarbohedrenes, suggesting that late transitional metals should not lead to the formation of stable members of this cla ss of clusters due to their rich d-electron character. The stability o f these binary metallocarbohedrenes provides further evidence that the se species do constitute another form of cluster, which have the poten tial of being the building blocks for useful new optical and catalytic materials.