isomer

[ ahy-suh-mer ]

noun

1. Chemistry. a compound displaying isomerism with one or more other compounds.
2. Also called nuclear isomer. Physics. a nuclide that exhibits isomerism with one or more other nuclides.

isomer

/ ˌaɪsəˈmɛrɪk; ˈaɪsəmə /

noun

1. chem a compound that exhibits isomerism with one or more other compounds
2. physics a nuclide that exhibits isomerism with one or more other nuclides

isomer

/ ī′sə-mər /

1. Chemistry.
   Any of two or more substances that have the same molecular formula but differ in their connectivity or spatial arrangement of atoms, or in their topology in macromolecules.
2. Physics.
   Any of two or more nuclei with the same mass number and atomic number that have different radioactive properties and can exist in any of several energy states for a measurable period of time.

Derived Forms

• isomeric, adjective

Word History and Origins

Origin of isomer¹

First recorded in 1865–70; back formation from isomeric

Example Sentences

The new workflow can also identify isomers, which are molecules with the same chemical formula but different atomic arrangements.

From Science Daily

In Xu and co-workers’ synthetic pathway, a UV-induced chemical reduction occurs that leads to the strikingly selective destruction of these unwanted by-products, ultimately producing only the biologically relevant isomers of the purines.

From Nature

Using mass spectrometry, researchers effectively identified glycan linkages, but in many instances failed to differentiate between sugar isomers.

From Nature

Switching the catalyst to its mirror image will therefore not switch the sign of the output in their model, and the model cannot predict which enantiomer is produced as the major isomer.

From Nature

This includes “all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers, whether growing or not.”

From Salon