isomerism


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isomerism

 [i-som´ĕ-rizm]
the possession by two or more distinct compounds of the same molecular formula, each molecule having the same number of atoms of each element, but in different arrangement.
Chain isomerism. From Dorland's, 2000.

i·som·er·ism

(ī-som'ĕr-izm),
The existence of a chemical compound in two or more forms that are identical with respect to percentage composition but differ as to the positions of one or more atoms within the molecules, as well as in physical and chemical properties.

isomerism

/isom·e·rism/ (-ah-rizm) the possession by two or more distinct compounds of the same molecular formula, each molecule having the same number of atoms of each element, but in different arrangement.
constitutional i.  isomerism in which the compounds have the same molecular formula (that is, they are composed of the same atoms) but differ in structure, the atoms being linked in different ways.
Constitutional isomerism. Both compounds have the molecular formula C4H10.
geometric isomerism  stereoisomerism in which isomers differ in the arrangement of substituents of a rigid structure, such as double-bonded carbon atoms or a ring.
optical isomerism  stereoisomerism in which isomers differ in the arrangement of substituents at one or more asymmetric carbon atoms; thus some, but not necessarily all, are optically active.
structural isomerism  constitutional i.

isomerism

Cardiology
A term referring to the development of right-sided and left-sided structures (e.g., the atria), on the right (termed right atrial isomerism), or left (termed left atrial isomerism) side.

Chemistry
The process by which one molecule is transformed into another with the same, albeit rearranged, atoms, which may occur spontaneously or require the input of energy.

Basic types of chemical isomerism:
• Structural isomerism, in which the isomers have the same chemical composition but differ from each other in the position (positional isomerism) of various molecules (e.g., of the halides—fluoride, chloride, bromide, etc.—or hydroxy groups), integral to their composition, as well as the integrity of their functional groups, which generally result in functional differences.

• Spatial isomerism, which is characterised by differences in geometric positioning of atoms and in which functional groups in space differ.

i·som·er·ism

(ī-som'ĕr-izm)
The existence of a chemical compound in two or more forms that are identical with respect to percentage composition but differ as to the positions of one or more atoms within the molecules, and also in physical and chemical properties.

isomerism

the phenomenon of two chemical compounds having the same formula but a different arrangement of atoms.

isomerism (ī·sōˑ·mer·i·zm),

n dissimilar arrangement of atoms within the molecules of two chemical compounds that have identical molecular formulae. See also geometric isomerism and optical isomers.
Enlarge picture
Isomerism.
isomerism, geometric,
n a form of isomerism in compounds containing at least one double bond where atoms or atomic groups attached to the doubly bound carbon atoms have no free rotation around the axis of the double bond. Geometric isomers with specific atomic groups on opposite sides of the double bond are called trans-isomers, while cis-isomers have those groups on the same side.

isomerism

the possession by two or more distinct compounds of the same molecular formula, each molecule having the same number of atoms of each element, but in different arrangement.
References in periodicals archive ?
Characteristics and natural history of abnormal atrial rhythms in left isomerism.
This is a more universal language to describe the abnormality identified, rather than using the basic terminology of asplenia/polysplenia/ isomerism where the exact constellation of findings will not be communicated to the referring clinician or fellow radiologist.
It could be optical isomerism or something, but I'm sure I'm right.
Some nutrition experts think this isomerism is significant, and that synthetic forms should be avoided; others think it is meaningless and the nutrients are equivalent.
But his parents are considering legal action after bosses at Inverclyde Royal Hospital admitted that the fatal condition - left atrial isomerism - had been missed by an experienced consultant at Michele's 20-week scan.
The early echocardiogram identified two cases of ectopia cordis, two cases of atrioventricular septal defect, two cases of hypoplastic left heart syndrome, two cases of ventricular septal defect, two cases of left atrial isomerism, two cases of hypoplastic right ventricle, and one case each of double outlet right ventricle and cardiac diverticulum.
This relationship was an example of isomerism (Greek: isomeros, composed of equal parts), a term proposed by Berzelius in 1831.
In a recent article in the Journal of the American Chemical Society (2002, 124:2474), Lubell and co-worker Liliane Halab, MCIC, describe the cis/trans isomerism in 5-tert-butyl proline containing peptides (see Figure 3).
9:00 A STUDY IN LINKAGE ISOMERISM FOR THE INORGANIC CHEMISTRY LABORATORY, Larry McRae, Berry College, P.
Linkage isomerism in trimeric and polymeric 2,3-cis-procyanidins.