dsp² Hybridization

In addition to above types of Hybridization, dsp² type of hybridization is also known particularly in case of transition metal ions. The orbitals involved in this type of Hybridization are d_x²_{- y}², s and two p. The four dsp² hybrid orbitals adopt square planar geometry.

Geometry of [Ni(CN)

₄]^2-

The complex ion [Ni(CN)₄]^2- involves dsp² Hybridization as explained below. In this case, the oxidation state of nickel is +2. The outer electronic configuration of Ni²⁺ is 3d⁸ as given in fig.1.30 (a).

fig 1.30 - Formation of [Ni(CN)₄]^2- involving dsp² Hybridization

fig 1.31 - Structure of [Ni(CN)₄]^2-

In the formation of the complex ion, the two unpaired d electrons are paired up making one 3d orbital empty. The four empty orbitals (one 3d, 4s and two 4p) hybridize to form four dsp² hybrid orbitals, which point towards square planar arrangement. Each one of the four CN- groups donates lone pair of electrons to vacant hybrid orbitals forming four Ni - CN bonds. Thus, [Ni(CN)₄]^2- has square planar arrangement as shown in fig.1.30.