In an octahedral structure, the pair of d-orbitalsinvolved in d 'sp hybridisation is

In an octahedral structure, the pair of d-orbitals involved in dsp^2 hybridization are d_z^2 and d_x^2-y^2.

Here's the step by step explanation:

1. In an octahedral structure, the central atom is surrounded by six other atoms, all located at the corners of an octahedron.

2. For the central atom to form bonds with these six atoms, it needs to have six available orbitals for bonding.

3. The hybridization that allows for six orbitals is d^2sp^3. However, in the question, we are asked about dsp^2 hybridization, which only allows for five orbitals.

4. In dsp^2 hybridization, one d-orbital, one s-orbital, and two p-orbitals are involved.

5. The d-orbitals that are usually involved in this type of hybridization are d_z^2 and d_x^2-y^2. These orbitals are chosen because they are the most symmetrical and cause the least amount of repulsion between the bonded atoms.

6. Therefore, in an octahedral structure, the pair of d-orbitals involved in dsp^2 hybridization are d_z^2 and d_x^2-y^2.