Isomerism

yes i too had the same question,.....

@nikunj. can you please tell me the formuila for optical isomers.. please!!

http://www.scribd.com/doc/2903780/How-to-find-no-of-structural-isomers-

is axis of symmetry and centre of symmetry from optical isomerismis in course of iit jee ?

The three factors which render a compound optically inactive : alternating axis of symmetry, point/centre of symmetry and plane of symmetry are there in syllabus.

No. of possible stereoisomerism in compounds having n-chiral carbon atoms
Case 1:-
wen der is no symmetry
number of d and l forms, a(say) = 2^n
no. of meso forms, m(say) = 0
total no of stereoisomerism = a+m = 2^n

Case 2
wen the molecule hs symmetry and n is even
den d no. of d & l forms , a = 2^(n-1)
the total no. of meso forms , m =2^(n/2 - 1)
total no. of meso forms = a+m

Case 3
wen d molecule can b divided into two parts & n is odd then
no. of d & l forms, a = 2^(n-1) -2^(n-1)/2
no.of meso forms,m = 2^(n-1)/2
total no. of stereoisomerisms = a+m

but brilliant tutorials have mentioned it out of syllabus of iit jee

there is a question reagarding the centre of symettry n axis of symettry in iit jee08. pls refer the paper jee08