Bicyclic molecule

[1] Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor.

[6][7][8] The root of the compound name depends on the total number of atoms in all rings together, possibly followed by a suffix denoting the functional group with the highest priority.

The carbon frame of camphor also counts 7 atoms, but is substituted with a carbonyl in this case, hence the suffix heptanone.

Besides bicyclo, the prefix should also specify the positions of all methyl substituents so the complete, official name becomes 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one.

The heterocyclic molecule DABCO has a total of 8 atoms in its bridged structure, hence the root name octane.

The bridged bicyclic norbornane , formally bicyclo[2.2.1]heptane
The spirocyclic compound spiro[5.5]undecane
DABCO (1,4-diazabicyclo[2.2.2]octane) is often incorrectly depicted with one skewed ethylene group for the sake of clarity.
C 8 , C 9 , and C 11 bicyclic alkanes . The bridgehead atoms are the carbons from which three bonds radiate, like spokes:bicyclo[2.2.2]octane, bicyclo-[3.3.1]nonane, bicyclo[3.3.3]undecane.