This molecular formula is applicable for homologous series ether (-O-) a bivalent functional group and as we know ether with minimum four-C shows metamerism. $\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\, \&\, \mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{3}$ are metamers.