ring systems that share more than two atoms are called bicyclic
bicyclic alkanes, you follow these three steps:
the total number of carbons in the entire molecule. This
is the parent name (eg. ten carbons in the system would
the number of carbons between the bridgeheads, then place
in brackets in descending order. (eg. [2,2,1])
the word bicyclo at the beginning of the name.
Name the following molecule by the IUPAC system of nomenclature.
the total number of carbons. In this case there are 7 carbons
so the parent name is heptane
the total number of carbons between bridgeheads. In this
case there are 2, 2, and 1 carbons between the bridgehead.
Placed in descending order between brackets it is [2,2,1]
the word bicyclo in the front of the name
is thus bicyclo [2,2,1] heptane
Now you try naming these (click on the molecule to get