How many isomers of C_4H_8Cl_2C4H8Cl2 are here? How do you tell if one structure is an isomer of another?

1 Answer
Jun 28, 2016

I count 13 isomers of "C"_4"H"_8"Cl"_2C4H8Cl2: 9 structural isomers and 4 optical isomers,

Explanation:

I find that the easiest way to tell if one structure is an isomer of another is to write their IUPAC names.

Each isomer will have a unique name.

We use a systematic procedure to generate the structures.

A. Base chain is 1-chlorobutane

1,1-Dichlorobutane

1,1-dichloro

(RR)- and (SS)-1,2-Dichlorobutane

1,2-dichloro

(RR)- and (SS)-1,3-Dichlorobutane

1,3-dichloro

1,4-Dichlorobutane

1,4-dichloro

B. Base chain is 2-chlorobutane

2,2-Dichlorobutane

2,2-dichloro

(2R,3R)"-", (2S,3S)2R,3R)-,(2S,3S)-, and (2R,3S2R,3S)-2,3-Dichlorobutane

3 Optical isomers

C. Base is 1-chloro-2-methylpropane

1,1-dichloro-2-methylpropane

1,1-dichloro

1,2-Dichloro-2-methylpropane

1,2-dichloro

1,3-Dichloro-2-methylpropane

1,3-dichloro