`ClF_(3)` molecule has a bent T-shaped structure and not a trigonal planar structure. Explain.

Explanation

The electronic configuration of Cl (Z = 17) is `1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p_(x)^(2) 3p_(y)^(2) 3p_(z)^(1)`. It has only one half-filled orbital. But to form three Cl-F bonds, we need three half-filled orbitals. To achieve this, one of the `3p_(y)` electrons gets excited to 3d-orbital. The resulting five orbitals of the third shell of Cl in the first excited

state undergo `sp^(3)` d-hybridization to give T-shaped structure to `ClF_(3)` molecule. Since Cl does not undergo `sp^(2)`-hybridization, therefore, `ClF_(3)` does not have trigonal planar structure.