Mam/sir how we will get to know that how many structural isomers should be drawn for a particular compound ?
Mam/sir how we will get to know that how many structural isomers should be drawn for a particular compound ?
Determining the number of possible structures for a given range of chemical formulae isn't simple even for saturated hydrocarbons. The number of possible structural isomers rises rapidly with the number of carbons and soon exceeds your ability to enumerate or identify the options by hand. For example, lists the numbers of isomers and stereoisomers for molecules with up to 120 carbons. But the counts are getting silly even at 10 carbons where there are 75 isomers and 136 stereoisomers.
There isn't any formula for structural isomers. But there are formulas for stereo isomers. If there are n chiral carbons in a molecule, then the following two cases may arise.
case 1: The ends of the molecule are asymmetric. In this case the number of structural isomers are 2n2n and all of them are optically active.
case2: The ends of the molecule is symmetric. Following two cases may arise
case 2a. n is even. In this case number of optically active form=2(n−1)2(n−1) Number of meso isomers is 2(0.5n−1)2(0.5n−1) and the total number of stereo isomer is the summation of these two.
case 2b. n is odd. In this case total number of stereo isomer is 2(n−1).2(n−1). Number of meso isomers is 2(0.5n−0.5)2(0.5n−0.5) and the number of optically active forms is the difference of these two.
Hope this helps :)
There isn't any formula for structural isomers. But there are formulas for stereo isomers. If there are n chiral carbons in a molecule, then the following two cases may arise.
case 1: The ends of the molecule are asymmetric. In this case the number of structural isomers are 2n2n and all of them are optically active.
case2: The ends of the molecule is symmetric. Following two cases may arise
case 2a. n is even. In this case number of optically active form=2(n−1)2(n−1) Number of meso isomers is 2(0.5n−1)2(0.5n−1) and the total number of stereo isomer is the summation of these two.
case 2b. n is odd. In this case total number of stereo isomer is 2(n−1).2(n−1). Number of meso isomers is 2(0.5n−0.5)2(0.5n−0.5) and the number of optically active forms is the difference of these two.
Hope this helps :)
