Carboranes of intermediate nuclearity are most efficiently generated by degradations from larger clusters.  In contrast, smaller carboranes are usually prepared by building-up routes, e.g. from pentaborane + alkyne, etc.
For example ortho-carborane can be degraded to give , which can be manipulated with oxidants, protonation, and thermolysis.
Chromate oxidation of 11-vertex clusters results in deboronation, giving . From that species, other clusters result by pyrolysis, sometimes in the presence of diborane: .
In general, isomers having non-adjacent cage carbon atoms are more thermally stable than those with adjacent carbons.  Thus,  heating tends to induce mutual separation of the carbon atoms in the framework.