Are methyl n-propyl ether and methyl iso-propyl ether metamers?
It says so here.

So the difference must be in number of carbon atoms or the distribution?


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    $\begingroup$ en.wikipedia.org/wiki/Metamerism I agree with @lighthart. Metamerism seem to be a limited definition of isomerism. As so it's chosen to be obsolete, you mustn't worry about it. $\endgroup$ – It's Over Mar 27 '15 at 18:25

The term metamer is equivalent to isomer. Isomers differ in connectivites of atoms between molecules with the identical number and type of atoms.

Methyl n-propoyl Ether and methyl iso-propyl ether have the same numbers of carbon, oxygen and hydrogen atoms.

As an aside, I have never heard the term metamer before, I expect it is archaic.

  • $\begingroup$ Did you check that link? It has a definition. $\endgroup$ – ChemExchange Mar 27 '15 at 16:40
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    $\begingroup$ Neither have I. It isn't in the Gold Book either. $\endgroup$ – Klaus-Dieter Warzecha Mar 27 '15 at 16:52
  • $\begingroup$ dictionary.reference.com/browse/metamerism @KlausWarzecha $\endgroup$ – ChemExchange Mar 27 '15 at 16:55
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    $\begingroup$ @ChemExchange Irrelevant! No IUPAC, no cigar. $\endgroup$ – Klaus-Dieter Warzecha Mar 27 '15 at 16:58
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    $\begingroup$ I think metamer has an interesting specification: it has to have the same molecular formula and the same functional group. While we could just say "isomeric ethers" or something, I think it's a cool concept, but I'll probably never use it, and it doesn't make much difference as far as this question goes. Now if the question had been about 1-methoxypropane and 2-methyl-1-propanol, that would come into play. $\endgroup$ – SendersReagent Apr 28 '16 at 3:42

Compounds having the same molecular formula but different number of carbon atoms ( alkyl groups) on either side of functional group ( i.e., $\ce{-O-,-S-, -NH-, -C(=O)-}$) are called metamers and the phenomenon is called metamerism. metamerism occurs amongst the members of the same homologus family.

For example:

  • $\ce{CH3CH2-O-CH2CH3}$ is a metamer of $\ce{CH3-O-CH2CH2CH3}$ OR $\ce{CH3-O-CH(CH3)2}$

  • $\ce{CH3CH2COCH2CH3}$ is a metamer of $\ce{CH3COCH2CH2CH3}$ OR $\ce{CH3COCH(CH3)2}$

It may be noted that metamers may also be position isomers, e.g., pentan-2-one and pentan-3-one may be regarded as position isomers as well as metamers.


It is a type of positional isomerism in which functional group changes its position in the backbone of parent chain,methyl propyl ether and methylisoptopyl ether are metamers from Above def.


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