Which kind of isomerism is exhibited by `[Co(EDTA)]`-

Options

A. Optical & geometrical isomerism
B. Geometrical isomerism
C. Optical isomerism
D. no isomerism

Explanation

To determine the type of isomerism exhibited by the complex `[Co(EDTA)]`, we can follow these steps:

### Step 1: Identify the Ligand and Its Denticity
EDTA (ethylenediaminetetraacetic acid) is a hexadentate ligand, meaning it can form six bonds with a metal ion. It has two nitrogen atoms and four carboxylate groups that coordinate to the metal.

**Hint:** Remember that the denticity of a ligand refers to the number of donor atoms it has that can coordinate to a metal center.

### Step 2: Analyze the Coordination Geometry
Cobalt typically exhibits octahedral geometry when coordinated with six donor atoms. In the case of `[Co(EDTA)]`, the six donor atoms from EDTA will occupy the vertices of an octahedron around the cobalt ion.

**Hint:** Consider the geometry of the complex formed by the ligand and the metal ion, as it can influence the type of isomerism.

### Step 3: Consider Possible Isomerism Types
In coordination complexes, the main types of isomerism include:
- Geometrical isomerism (cis/trans)
- Optical isomerism (enantiomers)
- Linkage isomerism
- Coordination isomerism

For `[Co(EDTA)]`, geometrical isomerism (cis/trans) is typically observed in complexes where there are different arrangements of ligands around the metal ion.

**Hint:** Think about whether the arrangement of the ligands can lead to different spatial configurations.

### Step 4: Evaluate Geometrical Isomerism
In the case of `[Co(EDTA)]`, due to the nature of the EDTA ligand and its ability to form chelate rings, there are no distinct cis or trans configurations possible. The complex does not have a plane of symmetry, which means it cannot exhibit geometrical isomerism.

**Hint:** Check if the complex can have different arrangements of ligands that lead to distinct geometrical forms.

### Step 5: Determine Optical Isomerism
Since `[Co(EDTA)]` does not have a plane of symmetry and cannot exhibit geometrical isomerism, it can exhibit optical isomerism. This means that the complex can exist in two non-superimposable mirror images (enantiomers).

**Hint:** Optical isomerism is often indicated by the absence of symmetry elements in the structure.

### Conclusion
The complex `[Co(EDTA)]` exhibits optical isomerism due to the lack of a plane of symmetry and the presence of chiral centers in the arrangement of the ligand around the cobalt ion.