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paddlane

n. (context chemistry English) any tricyclic saturated hydrocarbon having two bridgehead carbon atoms joined by four bridges

Wikipedia
Paddlane

In organic chemistry, paddlane is any member of a class of tricyclic saturated hydrocarbons having two bridgehead carbon atoms joined by four bridges. The name derives from a supposed resemblance of the molecule to a paddle wheel: namely, the rings would be the propeller's blades, and the shared carbon atoms would be its axis.

Systematically named tricyclo [m.n.o.p]alkanes, these compounds have been referred to as [m.n.o.p]paddlanes. The notation [m.n.o.p]paddlane means the member of the family whose rings have m, n, o, and p carbons, not counting the two bridgeheads; or m + 2, n + 2, o + 2, and p + 2 carbons, counting them. The chemical formula is therefore CH. When p = 0, the compounds are propellanes.