isomer
UK[ˈaɪ.sə.mə]US[ˈaɪ.sə.mɚ]
n
Each of two or more compounds with the same molecular formula but a different arrangement of atoms and different properties.
n
Each of two or more atomic nuclei with the same atomic number and mass number but different energy states.
Morpheme Breakdown
iso
mer
iso
equal
mer
part
Etymology
The term 'isomer' is a modern scientific coinage, constructed directly from ancient Greek roots to describe a precise chemical concept. It combines iso- (equal) and -mer (part) to literally mean "having equal parts," referring to the identical numbers and types of atoms in the molecules. The logic of the word captures the core paradox of isomers: they are composed of the same 'parts' (atoms) in equal measure, yet the arrangement of those parts differs, leading to distinct substances. This elegant formation from Greek elements allows for a clear, descriptive term in the international language of science.
Analysis
Structure: iso (equal) + mer (part)
- iso: From Greek isos, meaning "equal, same, identical." It functions as a combining form in scientific terminology.
- mer: From Greek meros, meaning "part, share, portion." It functions as a combining form denoting a part or segment.
Examples
Butane and isobutane are isomers, both with the formula C4H10.
The chemist studied the different properties of the geometric isomers.
Nuclear isomers can release energy as gamma radiation when they decay to a more stable state.