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1. The phenomenon of the existence of isomers.
2. The complex of chemical and physical phenomena characteristic of or attributable to isomers.
3. The state or condition of being an isomer.


1. (Chemistry) the existence of two or more compounds having the same molecular formula but a different arrangement of atoms within the molecule. See also stereoisomerism, optical isomerism
2. (General Physics) the existence of two or more nuclides having the same atomic numbers and mass numbers but different energy states


(aɪˈsɒm əˌrɪz əm)

1. the relation of two or more compounds, radicals, or ions that are composed of the same kinds and numbers of atoms but differ from each other in structural or spatial arrangement.
2. the relation of two or more nuclides that have the same atomic number and mass number but different energy levels and half-lives.
3. the state or condition of being isomerous.
i•so•mer•ic (ˌaɪ səˈmɛr ɪk) adj.
i`so•mer′i•cal•ly, adv.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.isomerism - the state of being an isomer; the complex of chemical and physical phenomena characteristic of isomers
state - the way something is with respect to its main attributes; "the current state of knowledge"; "his state of health"; "in a weak financial state"
References in periodicals archive ?
By it, it will be fast and easy to arrange new business, insert external memorizers and conform isomerism space without any worries about the difficulties on memory writing management when dealing with new-brought equipments, configuration adjustment, and business interruption and so on.
Covering first metal complexes then transition metal chemistry, they discuss such topics as the correct empirical formula of complexes, isomerism and stereochemistry, metal carbonyls and nitrosyls, the vanadium group, and the actinides.
A 9-year-old girl presented with left atrial isomerism, complete atrioventricular septal defect, unbalanced ventricles (with right ventricle dominance, left ventricular hypoplasia) and double outlet right ventricle, pulmonic stenosis and PDA.
Our literature search in these aspects also indicated that these compounds possess rotational isomerism and they interconvert at room temperature (Deslypere 1995).
As with many organic molecules, there are possibilities for conformational isomerism due to internal hydrogen bonding within the molecule.
Air Force officers should also be familiar with the fundamental chemical phenomena, concepts, and classification: elements, compounds, affinity and stability, ionization, isomerism, and the periodic table.
The couple said that a consultant at Yorkhill Hospital, Glasgow, agreed the heart defect - known as right atrial isomerism - should have been spotted.
In right isomerism both great vessels are positioned on the same side of the spine (either right or left), and in left isomerism, the IVC is usually interrupted and continues with the azygous vein towards the thorax.
1971) reported that numbers of double bounds and isomerism of long chain dietary fatty acids are factors inhibiting gram-positive bacteria.
The materials' engineering introduces different degrees of functionality due to polymorphism and isomerism.