Cis-dichlorobis(ethylenediamine)cobalt(III) chloride is obtained by heating a solution of trans-dichlorobis(ethylenediamine)cobalt(III) chloride, e.g. using a steam bath.

The racemate can be resolved into two enantiomers (Λ and Δ) by the formation of the d-α-bromocamphor-π-sulfonate salt.
The diastereomeric salts are separated by recrystallization.
 After their purification, the individual diastereomers are converted back to the chloride salt by reaction with ice cold hydrochloric acid.
Cis-dichlorobis(ethylenediamine)cobalt(III) chloride is obtained by heating a solution of trans-dichlorobis(ethylenediamine)cobalt(III) chloride, e.g. using a steam bath.
The racemate can be resolved into two enantiomers (Λ and Δ) by the formation of the d-α-bromocamphor-π-sulfonate salt. The diastereomeric salts are separated by recrystallization.  After their purification, the individual diastereomers are converted back to the chloride salt by reaction with ice cold hydrochloric acid.
Cis-Dichlorobis(ethylenediamine)cobalt(III) chloride