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 several theoretical studies, providing indications of some shortcomings and pointing out useful directions for future experimental work. Moreover, the findings provide further insight into the mechanisms responsible for the formation of metallocarbohedrenes. They show that the formation of sigma-bonds between metal atoms and C-2 units are the key to the stability of metallocarbohedrenes, suggesting that late transitional metals should not lead to the formation of stable members of this class of clusters due to their rich d-electron character. The stability of these binary metallocarbohedrenes provides further evidence that these species do constitute another form of cluster, which have the potential of being the building blocks for useful new optical and catalytic materials.