Which of the following statements is/are correct?
(i) In octahedral complexes, `t_(2g)` orbitals posses low energy as compared to `e_g` orbitals
(ii) In tetrahedral complexes , `t_2` orbitals posses high energy as compared to e orbitals
(iii) In octahedral complexes , `e_g` orbitals possess low energy as compared to `t_(2g)` orbitals

Options

A. (ii) only
B. (iii) only
C. (i) and (ii)
D. (i) and (iii)

Answer

To solve the question, we need to analyze the statements regarding the energy levels of orbitals in octahedral and tetrahedral complexes. Let's break down each statement step by step:

### Step 1: Analyze Statement (i)
**Statement (i)**: In octahedral complexes, `t_(2g)` orbitals possess low energy as compared to `e_g` orbitals.

- In octahedral complexes, the crystal field splitting leads to the formation of two sets of orbitals: `t_(2g)` and `e_g`.
- The `t_(2g)` orbitals (which include the dxy, dxz, and dyz orbitals) are lower in energy compared to the `e_g` orbitals (which include the dz² and dx²-y² orbitals).
- Therefore, this statement is **correct**.

### Step 2: Analyze Statement (ii)
**Statement (ii)**: In tetrahedral complexes, `t_2` orbitals possess high energy as compared to `e` orbitals.

- In tetrahedral complexes, the crystal field splitting is reversed compared to octahedral complexes.
- The `t_2` orbitals (which include the dxz, dyz, and dxy orbitals) are higher in energy than the `e` orbitals (which include the dz² and dx²-y² orbitals).
- Therefore, this statement is also **correct**.

### Step 3: Analyze Statement (iii)
**Statement (iii)**: In octahedral complexes, `e_g` orbitals possess low energy as compared to `t_(2g)` orbitals.

- As previously discussed, in octahedral complexes, the `e_g` orbitals are higher in energy compared to the `t_(2g)` orbitals.
- Therefore, this statement is **incorrect**.

### Conclusion
Based on the analysis:
- Statement (i) is correct.
- Statement (ii) is correct.
- Statement (iii) is incorrect.

Thus, the correct answer is that statements (i) and (ii) are correct.

### Final Answer
The correct statements are (i) and (ii).

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