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
3.9 Reason of Occurrence of geometrical 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
3.2 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
When the two atoms are joined together by a double bond $\left( { > C = C < } \right),$ one pi and one sigma, free rotation about the carbon-carbon double bond becomes restricted (hindered) hence the spatial arrangements of atoms (or) groups attached with these carbon atoms becomes fixed in space and it represents two different isomers. Thus lack of free rotation about carbon-carbon double bond gives rise to geometrical isomersm.
In general the necessary and sufficient conditions for the occurrence of geometrical isomersm are (i) restricted (hindered) rotation of the carbon-carbon double bond and (ii) both the doubly bonded carbons should have different substituents.
Van’t Hoff explained the occurrence of cis-trans isomers on the basis of tetrahedral conception of carbon atom. According to him a double bond may be created by placing the two tetrahedrons edge-to-edge; such an arrangements would be rigid and free rotation around the double bond would be restricted.
Thus for a compound of the general formula abc=cab, two spatial models can be constructed where free rotation would be impossible.
The simple examples showing geometrical isomerism are given below.
2-Butene
3-Hexene
Maleic and Fumaric acids
