STEREO ISOMERS

STEREO ISOMERS

stereoisomers:-  two or two more than the same molecular formula same structural formula but a different arrangement of atom or group in space in three dimensional. 

two enatiomers of tetrahedral compound 

types of stereoisomers:-it is two types1) geometrical isomers    2) optical isomers geometrical isomers:-these isomers occurs where you have restricted rotation somewhere in a molecule.alkene(c=c)  azo(N=N) so the geometrical isomers.due to the restricted rotation of about double bond while cyclo alkane so....geometrcal isomers due to restricted rotation about single bond.......

condition for geometrical isomers;-1)only those alkene show geometrical isomers in which sp2 c- have different atom or group. a) cis -type:- when two CH3 atoms are locked on the same side is called cis isomers.b)trans-type:-when two CH3 atoms are locked on the opposite side is called as trans-isomers.

the most likely example of geometrical isomers is 1,2-dichloroethene.

properties cis-trans isomers:-stability:-    cis<trans because of less repulsion between the similar group in trans.2)dipole moment:-cis>trans 3)polarity:-more dipole moment more polarity.     cis>trans  4)solubility and boiling point:_cis >trans 
5)melting point:- trans >cis E AND Z SYSTEM:-E system mense trans and Z system mense cis.geometrcal isomers in cycloalkane:-cycloalkane so geometrical isomers due to restricted rotation about single bond only those.  cycloalkane so geometrical isomers in which at list two different C-present in two different groups. 

how to find geometrical isomers:-1) if N1 is not equal to N2 than no of geometrical isomers  2ⁿwhere n= to a number of the double bonds.2) if N1 is equal to  N2 then.......

$2^{n-1}+2^{p-1}$

$p=\frac{n}{2}$ (if $n$ is even)

$p=\frac{n+1}{2}$ (if $n$ is odd)

$\therefore$Total number of geometrical isomers is$=2^{n-1}+2^{p-1}=2^{2-1}+2^{\frac{2}{2}-1}=2^1+2^0=2+1=3$

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