Enantiomorphs (or enantiomers) are mirror images that are non-superimposable, a property known as chirality or optical activity. This typically occurs in octahedral complexes involving didentate ligands.
- Analysis of [Co(en)₂Cl₂]Cl: The complex ion is [Co(en)2Cl2]+. This is an octahedral complex of the type [M(AA)2a2], where 'AA' is the bidentate ligand ethylenediamine (en) and 'a' is the monodentate ligand chloride (Cl−).
- It exhibits Geometrical Isomerism (cis and trans).
- The Trans-isomer has a plane of symmetry and is optically inactive (achiral).
- The Cis-isomer lacks a plane of symmetry and is chiral. Therefore, the cis-isomer exists as a pair of enantiomorphs (dextro and laevo forms) .
- Other Options:
[Co(NH3)4Cl2]NO2: Type [Ma4b2]. The cis-isomer is usually considered achiral in this context relative to the chelated complex, and the trans-isomer is definitely achiral. [Cr(NH3)6][Co(CN)6]: Both ions are highly symmetrical octahedral species and do not show optical isomerism.
- [Pt(NH3)4][PtCl6]: Contains a square planar cation and octahedral anion, neither of which supports enantiomerism in this form.
Therefore, [Co(en)2Cl2]Cl is the compound that gives a pair of enantiomorphs.