JEE Main · 2020 · Shift-IImediumBOND-158

The molecule in which hybrid MOs involve only one d-orbital of the central atom is:

Chemical Bonding · Class 11 · JEE Main Previous Year Question

Question

The molecule in which hybrid MOs involve only one d-orbital of the central atom is:

Options
  1. a

    [Ni(CN)4]2\mathrm{[Ni(CN)_4]^{2-}}

  2. b

    BrF5\mathrm{BrF_5}

  3. c

    XeF4\mathrm{XeF_4}

  4. d

    [CrF6]3\mathrm{[CrF_6]^{3-}}

Correct Answera

[Ni(CN)4]2\mathrm{[Ni(CN)_4]^{2-}}

Detailed Solution

🧠 Identify which complex/molecule uses exactly one d-orbital in its hybridization scheme.

🗺️ Count d-orbitals in each hybridization:

| Species | Hybridization | d-orbitals used | |---------|--------------|----------------| | [Ni(CN)4]2\mathrm{[Ni(CN)_4]^{2-}} | dsp² (square planar, Ni²⁺ is d⁸ strong field) | 1 ✓ | | BrF5\mathrm{BrF_5} | sp³d² (5 bonds + 1 LP = 6 pairs) | 2 ✗ | | XeF4\mathrm{XeF_4} | sp³d² (4 bonds + 2 LP = 6 pairs) | 2 ✗ | | [CrF6]3\mathrm{[CrF_6]^{3-}} | d²sp³ (octahedral, 6 bonds = 6 pairs) | 2 ✗ |

⚡ In dsp² hybridization (e.g. square planar Ni²⁺ complexes), the d-orbital involved is the dx2y2d_{x^2-y^2} — just one. This is characteristic of strong-field d⁸ complexes.

Answer: [Ni(CN)4]2\boxed{\text{Answer: } \mathrm{[Ni(CN)_4]^{2-}}}

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