Naming alicyclic hydrocarbons are a tad complicated since there are different groups of hydrocarbons such as alkanes, alkenes, and alkynes. As you know, alkanes are compounds that contain only single bonds between the atoms, alkenes contain double bonds and alkynes have triple bonds. When each of those chains become a ring, there are obviously different ways in naming the result. However, they all have the same prefix of cyclo.
In cycloalkanes (the name for ringed alkanes) they sometimes have an attachment of an alky group and sometimes they don't. However though, no matter what, you'd still end off an cycloalkane with -ane.
No Attachments
When there is no alky group attached, you name the compound by the number of sides the shape of the ring has. For example a pentagon has five sides. When naming this you would end up with cyclopentane. The simplest shape you can have as a ring is a triangle.
With Attachments
On the other hand, when you have an alkyl group attached, you add the name of the group in front. When you have more than one alkyl group, then you again use the Greek prefixes. This means if you have a tertbutyl group attached to a cyclopentane, you would end up with tertbutylcyclopentane as a name.
Both cycloalkenes and cycloalkynes are similar when naming them. The only difference is the substitution of the ending. When you have a cycloalkene, you would use the ending ene and when you have a cycloakyne, you would use the ending yne. In both cases, it is possible to have more than one triple or double bond. In these situations, you would substitute the ending of the word with the number of bonds you have in front of it. For example, when you have two double bonds in a cyclopentene, it would turn into cyclopentdiene. An example of having three bonds in a cyclooctyne, it would turn into cycloocttriyne.
Spiranes
In a polynuclear ring (a compound that contains more than one ring), you have the prefix that indicates the number of rings instead of just cyclo-. An example is the prefix bicyclo- for 2 rings. To name the rest of the compound, the steps are similar in naming alicyclic hydrocarbons with containing one ring. There is a small difference though, you need to put brackets following the __cyclo- prefix and state the number of carbons surrounding the central (connecting) carbon in decreasing order. For example: This compounds name is bicyclo(4,4,0)decane. The explanation is:
-It is a ring (cyclo-)
-There is 2 rings (bi-)
-The first "4" represents the 4 CH groups that surround one of the central carbons
-The second "4" represents the 4 CH groups that surround the second central carbon
-The "0" represents the the fact that there are not any CH groups in between the two central carbons
-There are 10 carbons in the compound (-dec)
-There are only single bonds (-ane)
When you have a spirane (you have the prefix spiro-. Then you again state the number of carbons in decreasing order following the prefix. Then you follow the normal steps in naming the ending (Num. of carbons in the shape).
