Which orbit of the below forms the δ -bond?

Question

Question

This question was previously asked in

DSSSB PGT Chemistry (Female) Official Paper (Held On: 06 Jul, 2018 Shift 1)

Answer 1

CONCEPT:

δ (Delta) Bonds in Transition Metal Compounds

δ-bonds are formed by the sidewise overlap of two d-orbitals that have four lobes oriented between the axes.
These bonds are rarer and generally occur in compounds with metal–metal multiple bonding, especially in transition metal dimers.
To form a δ-bond, the orbitals must overlap sideways in such a way that the nodal planes pass through the internuclear axis.

EXPLANATION:

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d_xy: Lobes lie between x and y axes → suitable for δ-bond
d_yz: Lobes between y and z axes → not ideal for δ-bond in typical M–M direction
d_z²: Lobes along z-axis → forms σ-bonds, not δ
d_x²−y²: Lobes along x and y axes → forms σ-bonds, not δ

Therefore, the orbital that forms a δ-bond is d_xy