7,8-(Dichloromethano)homo[70]fullerene, an unusual, but unexceptional, methanoannulene

The crystal structure of 7,8-(dichloromethano)homo[70]fullerene shows that addition of the dichlorocarbene (:CCl₂) to C₇₀ gives a surprisingly normal methano-bridged [9]annulene. The structural changes caused by the addition are highly localized; the C(7)-C(8) distance lengthens by 0.705(2) Å but no other distance changes by more than 0.022(3) Å. Bond angles within the [9]annulene increase by as much as 7.8(1)°, but changes outside the C₉ ring are much smaller. The nearly ellipsoidal molecules form hexagonally close-packed layers that interact in pairs through short Cl⋯C, and possibly short Cl⋯ and C⋯C, interactions.