I've been trying the get the number of isomers of bromocyclohexane and 1,2-dibromocyclohexane.I was taught that every cycloalkane should have an isomer that's an open chained alkene. I searched regarding this matter and I'm getting only the meta-para-ortho configuration, which is not what I wanted.

So, how can I get the open chain alkene for a cycloalkane with which I would get the correct number of isomers?

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    $\begingroup$ As it happens, the word "isomer" by itself can be pretty confusing. If you were told to count the isomers of (say) C6H12, then those indeed would include some cycloalkanes and some open chained alkenes. But if you are told explicitly to deal with cyclo-something, then it is only cyclic isomers. Also, welcome to Chem.SE. $\endgroup$ – Ivan Neretin Feb 7 '17 at 6:19
  • $\begingroup$ @IvanNeretin Hey, what would you name this isomerism between cycloalkanes and their open chain alkenes? Chain Isomerism? $\endgroup$ – Mockingbird Feb 8 '17 at 1:03
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    $\begingroup$ @Mockingbird en.wikipedia.org/wiki/… $\endgroup$ – Ivan Neretin Feb 8 '17 at 5:37
  • $\begingroup$ @Rej I counted the number of possible open chain alkene isomers of bromocyclohexane. It's 69. $\endgroup$ – Mockingbird Feb 10 '17 at 2:19

Yeah, they do. Look, every non-substituted cycloalkane has a general formula of CnH2n which is same for a open chain alkene. So, every cycloalkane one or more than one(if that alkene has some isomers(e.g. chain or position isomer) open chain alkene isomer.

For example, cyclopropane(C3H6)has only one open chain alkene isomer which is prop-1-ene. But cyclobutane(C4H8) has 4.

I won't elaborate more as you should work it out on your own.


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