Isomerism
1.0 Isomerism
2.0 Structural Isomerism
2.1 Chain or Nuclear Isomerism
2.2 ${C_5}{H_{12}}$ stands for three chain isomers
2.3 Cyclohexane and methyl cyclopentane are nuclear isomerism
2.4 Position Isomerism
2.5 Functional Isomerism
2.6 Metamerism
2.7 Ring Chain Isomerism
3.0 Tautomerism
3.1 Structural requirement for tautomrism
3.2 Cause of tautomerism
3.3 Keto-enol tautomerim
3.4 Percentage Composition of Tautomeric Mixture
3.5 Triad System containing Nitrogen
3.6 Mechanism of tautomerism
3.7 Stereoisomerism
3.8 Geometrical Isomerism
3.9 Reason of Occurrence of geometrical Isomerism
4.0 Geometrical isomerism in the compounds containing C=N
4.1 Geometrical isomerism in the compounds containing N=N
4.2 Geometrical Isomerism in Cyclic Compounds
4.3 Stability of cis, Trans (or) Geometrical isomers
4.4 Number of Geometrical isomers
4.5 E and Z nomenclature of geometrical isomers
5.0 Optical Isomerism
5.1 Optical Activity
5.2 Asymmetric carbon (or) Chiral Carbon
5.3 Optical isomerism in bromo chloro iodo methane
6.0 Optical isomerism in compounds having more than one chiral carbons
6.1 Elements of symmetry
6.2 Centre of Symmetry
6.3 Stereoisomerism in Tartaric Acid
6.4 Calculation of number of optical isomers
7.0 Optically active compounds having no asymmetric carbon
6.3 Stereoisomerism in Tartaric Acid
2.2 ${C_5}{H_{12}}$ stands for three chain isomers
2.3 Cyclohexane and methyl cyclopentane are nuclear isomerism
2.4 Position Isomerism
2.5 Functional Isomerism
2.6 Metamerism
2.7 Ring Chain Isomerism
3.2 Cause of tautomerism
3.3 Keto-enol tautomerim
3.4 Percentage Composition of Tautomeric Mixture
3.5 Triad System containing Nitrogen
3.6 Mechanism of tautomerism
3.7 Stereoisomerism
3.8 Geometrical Isomerism
3.9 Reason of Occurrence of geometrical Isomerism
4.2 Geometrical Isomerism in Cyclic Compounds
4.3 Stability of cis, Trans (or) Geometrical isomers
4.4 Number of Geometrical isomers
4.5 E and Z nomenclature of geometrical isomers
5.2 Asymmetric carbon (or) Chiral Carbon
5.3 Optical isomerism in bromo chloro iodo methane
6.2 Centre of Symmetry
6.3 Stereoisomerism in Tartaric Acid
6.4 Calculation of number of optical isomers
Compounds which contain two asymmetric carbon atoms and are of the type $Cabc–Cabc$ exist in only three isomeric forms. Two of these are non-superimposable mirror images of each other and are optically active and the third, a diastereomer of the first two, contains a plane of symmetry, is super imposable on its mirror image, and is not optically active, e.g.
The inactive diastereomer is usually described as a meso form. As with other examples of diastereomers, the properties of meso forms are different from those of the isomeric mirror-image pairs; for example, mesotartaric acid melts at a lower temperature $\left[ {140^\circ C} \right]$ than the d and $\ell $ isomers $\left[ {170^\circ C} \right],$ and is less dense, less soluble in water, and a weaker acid.
Compounds with two asymmetric carbon atoms in which at least one substituent in not common to both carbons occur in four optically isomeric forms, e.g., the four isomers of structure.
In general, a compound possessing n distinct asymmetric carbon atoms exists in optically active forms.
It should be noted that, whereas (i) and (ii) and (iii) and (iv) are mirror-image pairs and therefore have identical properties in a symmetric environment, neither of the (i) and (ii) bears a mirror-image relationship to either of those (iii) and (iv). These and other stereoismers which are not enantiomers are described as diastereomers (or diastereo isomers) and, unlike enantiomers, they differ in physical and chemical properties.
