Molecular wheel to monocyclic ring transition in boron-carbon mixed clusters C2B6 ̄ and C3B 5 ̄

In this joint experimental and theoretical work we present a novel type of structural transition occurring in the series of CxB 8-x ̄ (x = 1-8) mixed clusters upon increase of the carbon content from x = 2 to x = 3. The wheel to ring transition is surprising because it is rather planar-to-linear type of transition to be expected in the series since B8, B8 ̄, B8 2- and CB7 ̄ are known to possess wheel-type global minimum structures while C8 is linear. © 2011 the Owner Societies.