Which of the following statements are not correct ?

Options

A. If `Delta_(0)` lt P , low spin state is more stable .
B. CO is a very weak ligand.
C. The colour of a complex depends only on the nature of metal ion.
D. Tetrahedral complexes have nearly 50% CFSE value than octahedral complexes .

Explanation

To solve the question of identifying which statements are not correct regarding coordination compounds, we will analyze each statement step by step.

### Step 1: Analyze Statement A
**Statement A:** If ΔO < P, low spin stable is more stable.

**Analysis:**
- ΔO represents the crystal field splitting energy.
- P represents pairing energy.
- If ΔO is less than P, it indicates that the energy required to pair electrons is greater than the energy gained from splitting. Hence, low spin complexes are more stable in this case.

**Conclusion:** This statement is **correct**.

### Step 2: Analyze Statement B
**Statement B:** COE is a very weak ligand.

**Analysis:**
- CO (carbon monoxide) is known to be a strong field ligand due to its ability to cause significant splitting of d-orbitals and stabilize low spin complexes.
- Thus, the statement claiming CO as a weak ligand is incorrect.

**Conclusion:** This statement is **not correct**.

### Step 3: Analyze Statement C
**Statement C:** The color of complex depends only on the nature of metal ion.

**Analysis:**
- The color of a coordination complex is influenced not only by the nature of the metal ion but also by the ligands attached and the presence of unpaired electrons.
- Therefore, stating that it depends "only" on the metal ion is misleading.

**Conclusion:** This statement is **not correct**.

### Step 4: Analyze Statement D
**Statement D:** Tetrahedral complexes have nearly 50% CFSE value than octahedral complexes.

**Analysis:**
- Crystal Field Stabilization Energy (CFSE) for tetrahedral complexes is indeed about 50% of that for octahedral complexes due to the difference in the splitting of d-orbitals in these geometries.
- Thus, this statement is correct.

**Conclusion:** This statement is **correct**.

### Final Conclusion
The statements that are **not correct** are:
- Statement B: COE is a very weak ligand.
- Statement C: The color of complex depends only on the nature of metal ion.