Names and Physical Properties of Cycloalkanes

Many organic compounds found in nature contain rings of carbon atoms.  These compounds are known as cycloalkanes. Cycloalkanes have one or more rings of carbon atoms. Cycloalkanes only contain carbon-hydrogen bonds and carbon-carbon single bonds.  The simplest examples of this class consist of a single, un-substituted carbon ring, and these form a homologous series similar to the unbranched alkanes.

Like alkanes, cycloalkane molecules are often drawn as skeletal structures in which each intersection between two lines is assumed to have a carbon atom with its corresponding number of hydrogens.   Cyclohexane, one of the most common cycloalkanes is shown below as an example. 

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Cyclic hydrocarbons have the prefix "cyclo-". The IUPAC names, molecular formulas, and skeleton structures of the first ten cycloalkanes are given in Table 1.1. Note that the general formula for a cycloalkane composed of n carbons is C_nH_2n, and not C_nH_2n+2 as for alkanes.  Although a cycloalkane has two fewer hydrogens than the equivalent alkane, each carbon is bonded to four other atoms so are still considered to be saturated with hydrogen.

Table 1.1: Examples of Simple Cycloalkanes
Cycloalkane	Molecular Formula	Skeleton Structure
Cyclopropane	C3H6
Cyclobutane	C4H8
Cyclopentane	C5H10
Cyclohexane	C6H12
Cycloheptane	C7H14
Cyclooctane	C8H16
Cyclononane	C9H18
Cyclodecane	C10H20