isomerism definition

  • noun:
    • The phenomenon of this existence of isomers.
    • The complex of chemical and real phenomena characteristic of or attributable to isomers.
    • their state or problem to be an isomer.
    • the event of the presence of isomers - the presence of various substances with the exact same molecular formulae
    • the interconversion of isomers
    • their state, quality, or connection, of several isomeric substances.
    • In chem., identification or close similarity of structure and molecular fat, with distinction of physical or of both substance and physical properties.
    • in widest sense this term is applied to any a couple of chemical substances having the exact same portion structure. Numerous degrees and types of isomerism tend to be distinguished, the principal difference becoming between substance and physical isomerism. Chemical isomerism might be subdivided as follows: Polymerism, which is applied to substances with similar portion composition, however with molecular weights varying by some constant worth: instance, ethylene. C2H4, and butylene, C4H8, molecular loads 28 and 56 correspondingly. Polymerism might be either accidental or generic, in accordance with perhaps the substances fit in with the same or different classes. Metamerism is applied to compounds with similar portion composition and molecular fat, but containing homologous radicals when you look at the molecule: instances tend to be propylamine, C3H7NH2, ethylmethylamine, C2H5NHCH3, and trimethylamine, N(CH3)3. Chain or nucleus isomerism characterizes compounds which may have similar amount of comparable atoms into the molecule, but in that the carbon atoms creating the nucleus tend to be in a different way grouped: as, regular butane, CH3CH2CH2CH3, and isobutane, (CH3)3CH. Position or place isomerism is out there in substances which have comparable nuclei but differ inside relative position of certain substituting atoms or radicals in this nucleus: as, major or α-propyl chlorid, CH3CH2CH2Cl, and secondary or β-propyl chlorid, CH3CHClCH3. Structural isomerism pertains to substances that have the exact same portion structure and molecular weight but differ when you look at the arrangement of atoms in their particles. Real isomerism characterizes substances which include different aggregations of chemically comparable molecules. It was very first used of substances that are today called geometrical, stereo-isomeric, or optically isomeric. Alloisomerism is a phrase sometimes put on geometrically isomeric substances certainly one of which can pass in to the other by the action of temperature Dynamical isomerism is put on substances which have perfectly comparable linkage and spatial arrangement of atoms, but which vary in power content, that is. in atomic movement. (Tanatar, Ann. Chem. (Liebig), 273, 55.) Geometrical isomerism or stereo-isomerism marks substances that have similar constitution, but which differ inside spatial arrangement of certain constituent radicals or atoms. Optical isomerism is placed on stereo-isomeric substances which vary in their action on a ray of polarized light: they both deflect it off to the right (dextrorotatory), left (levorotatory), or tend to be optically inactive (racemic or mesoform).
    • their state of being an isomer; the complex of chemical and physical phenomena characteristic of isomers

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