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Another type of molecule containing only sp3 hybridised C and H atoms connected by s bonds is possible with a ring of 3 or more C atoms.  These are the cycloalkanes which are fairly common in the world of organic chemistry, both man-made and natural.

Functional group prefix = cyclo- (review)

Physical Properties:
Like alkanes, the low polarity of all the bonds in cycloalkanes means that the only intermolecular forces between molecules of cycloalkanes are the very weak induced dipole - induced dipole forces, also known as van der Waals forces which are easily overcome.  As a result, compared to other functional groups, but like alkanes, cycloakanes tend to have low melting and boiling points.

They have a generic formula of CnH2n, (note: there 2 less H atoms compared to the analogous alkane).
The C3 to C6 cycloalkanes are shown below in a variety of representations.

Cyclopropane C3H6  
Cyclobutane C4H8  
Cyclopentane C5H10  
Cyclohexane C6H12  

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organic chemistry © Dr. Ian Hunt, Department of Chemistry University of Calgary