Metamerism

Metamerism may refer to:

• Metamerism (biology), in zoology and developmental biology, the property of having repeated segments, as in annelids
• Metamerism (color), in colorimetry, a kind matching of the colors that, based on differences in spectral power distribution, do not actually match
• In chemistry, the chemical property of having the same proportion of atomic components in different arrangements (obsolete, replaced with isomer). In organic chemistry, compounds having the same molecular formula but different number of carbon atoms (alkyl groups) on either side of functional group (i.e., -O-,-S-, -NH-, -C(=O)-,esters, amides,etc) are called metamers and the phenomenon is called metamerism. For example, ether with the molecular formula ${\displaystyle C_{4}H_{10}O}$ can have two structures.It is a rare type of isomerism and is generally limited to molecules that contain a divalent atom (such as sulfur or oxygen), surrounded by alkyl groups.

Diethyl ether and methyl propyl ether are examples for metamerism. Both have same molecular formula but different alkyl groups on both sides