Fac, mer isomerism is associated with which of the following general formula ?

Options

A. `[M(A A)_(2)]`
B. `[M(A A )_(3)]`
C. `[MABCD]`
D. `[MA_(3)B_(3)]`

Answer

To determine the general formula associated with facial (fac) and meridional (mer) isomerism, we can follow these steps:

### Step 1: Understand the Geometry of Coordination Compounds
Coordination compounds can exhibit different types of isomerism, including geometric isomerism. In octahedral complexes, the arrangement of ligands around the central metal atom can lead to different spatial configurations.

**Hint:** Remember that octahedral complexes have a central atom surrounded by six ligands.

### Step 2: Identify the Types of Isomerism
Facial isomerism occurs when three identical ligands occupy one face of the octahedron, while meridional isomerism occurs when three identical ligands occupy a plane that divides the octahedron into two equal halves.

**Hint:** Visualize the octahedron and how ligands can be arranged on its faces.

### Step 3: Determine the General Formula
For both fac and mer isomerism to occur, the coordination compound must have a specific arrangement of ligands. The general formula for a coordination compound that exhibits fac and mer isomerism is typically represented as MA3B3, where M is the central metal atom, A represents one type of ligand, and B represents another type of ligand.

**Hint:** The presence of three ligands of one type and three of another type is crucial for the formation of these isomers.

### Step 4: Conclusion
Thus, the general formula associated with facial and meridional isomerism is **MA3B3**.

**Final Answer:** The correct option is **D: MA3B3**.