Cis-trans isomerism in cyclic compounds arises from the restricted rotation around the carbon-carbon single bonds that form the ring structure.

Cis-trans isomerism, also referred to as geometric isomerism, is a specific type of stereoisomerism. This phenomenon occurs due to variations in the spatial arrangement of atoms or groups around a bond. In the case of cyclic compounds, the isomerism is primarily a consequence of the limited rotation around the carbon-carbon single bonds in the ring. This limitation exists because breaking the ring to permit rotation would require a substantial amount of energy, which is typically not available under standard conditions.

In cyclic compounds, cis isomers are characterized by substituent groups located on the same side of the ring, whereas trans isomers have substituent groups positioned on opposite sides of the ring. For instance, in a cyclohexane ring, if two methyl groups are situated on the same side, the compound is classified as a cis isomer. Conversely, if the two methyl groups are found on opposite sides of the ring, it is identified as a trans isomer.

The existence of cis-trans isomerism in cyclic compounds can considerably influence their physical and chemical properties. For example, cis isomers generally exhibit higher boiling points compared to trans isomers. This is attributed to the increased polarity and stronger intermolecular forces present in cis isomers. In contrast, trans isomers tend to be more stable than their cis counterparts due to their symmetrical structure, which is energetically more favorable.

In conclusion, cis-trans isomerism in cyclic compounds results from the restricted rotation around carbon-carbon single bonds within the ring structure. This restriction leads to distinct spatial arrangements of substituent groups, producing different isomers that possess unique physical and chemical properties.