cupola based hydrocarbons My favorite groups of shapes are cupolas. Are there hydrocarbons in the shape of these similar to how cubane is to a cube? If so how stable are they, and could you please give some general information about each one.
They would be highly unstable due to the inverted tetrahedral geometry of the carbons in the top face. Generally, a polyhedron can form the basis of a stable hydrocarbon if it has at most 3 edges for each corner. A big caveat is that the hydrocarbon will distort the shape if the angle strain is too great. I found that out in my computational research on prismanes.