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I am currently studying in class 12, and I realised that I have a couple of fundamental doubts in the classification of organic compounds which was not covered well in class 11. My doubts are not related to nomenclature, which I regard as one of my strong points rather, it is directed at the definitions of certain terms such as saturated, unsaturated, cyclic, aliphatic etc.

In lieu of this, I have a couple of questions which I would be highly appreciative any of you could answer. Thank You so much in advance.(P.S. You can simply respond with a yes if my understanding is correct)

Q.)Is a cyclic compound defined as a compound comprising of at least one cyclic ring? So it may also comprises of multiple open chains as long as it comprises of at least one cyclic ring.

enter image description here

E.g Will the above compound be considered to be a cyclic compound even though it also has open chains?

Q.) My second question is whether the terms saturated and unsaturated are only defined for hydrocarbons or for all organic compounds in general? This stems from the fact that I read that the definition of a saturated a compound is a compound that only has C-C bonds.

enter image description here

E.g Is the above compound, considered to be a saturated compound since it only has C-C?

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Query regarding cyclic compounds- yes your reasoning is correct. Your structure has multiple functional groups (C=C) and a cyclopropane ring. Look at the structure of cholestrol, it has a number of rings and a long chain as well.

Query regarding unsaturation: Saturated is a very old term in organic chemistry, dating back when the atomic structures and electrons did not exist. The meaning of saturated, even today is "chemically combined to the maximum extent, having no ability to combine further." The carbon atoms in cyclopropane are saturated in the sense that all the four valencies of each carbon atom are satisfied by four individual atoms.

You will also encounter another term called the degree of unsaturation, it is a related concept: It tells us how many rings or double bonds are in the molecule. Don't mix these two terms.

You are again right in the sense that saturated and unsaturated terminology is frequently used for carbon chains or cycles.

For example we say, saturated fatty acid and unsaturated fatty acid as shown below: enter image description here

We are silently ignoring the C=O bond in this usage.

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  • $\begingroup$ Thanks for your response. So is the second compound I have drawn(1-chloropropane) a saturated or an unsaturated compound? Thus it is also possible for derivatives of hydrocarbons to be termed as saturated compounds right? $\endgroup$
    – Arun
    Jun 9, 2020 at 5:59
  • $\begingroup$ Yes, 1-chloropropane will be considered as a saturated compound because there is no double bond in the carbon chain. Chains (linear or cyclic) and their derivatives without double bonds/ triple bonds in C to C will be considered saturated. $\endgroup$
    – AChem
    Jun 9, 2020 at 6:01
  • $\begingroup$ Thanks for your response ! An unrelated question which I know you will be able to clarify, alkanes only refer to acyclic saturated hydrocarbons right? Cyclic saturated hydrocarbons belong to the class of cycloalkanes right? $\endgroup$
    – Arun
    Jun 9, 2020 at 6:13
  • $\begingroup$ Yes, correct. Accept the answer if you understand it now. $\endgroup$
    – AChem
    Jun 9, 2020 at 6:23

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