Engineering Chemistry S Datta

302 ENGINEERING CHEMISTRY
Tetrahedral Complex
As is implied the tetrahedral complexes are sp 3 hybridised. The formation of such
complexes can be illustrated by the formation of tetramine nickel (II) sulphate complex. Atomic
number of Ni is 26. Complex cation is produced from Ni 2+ ion. The co-ordination of nickel is
four. So four lone pairs are donated of four ammonia molecules. On the basis of VBT [Ni(NH 3
) 4
] 2+
is formed as follows:
(a) Electronic configuration of Ni
8 2
in ground state (... 3d 4s )
2+
(b) Electronic configuration of Ni
in ground state
(c) Electronic configuration of Ni
3
in sp hybridised state
(d) Electronic configuration of Ni
2+
in [Ni(NH ) ] complex
34
2+
2+
3d 4s 4p
sp 3
×× ×× ×× ××
3
NH 3 NH 3 NH 3 NH 3
sp hybridised orbitals are
filled with paired electrons
donated by four NH ligands
The shape of the molecule is tetrahedral, it is paramagnetic in nature and the tetrahedral
structure is shown below in Fig. 13.8.
3
NH 3
HN 3
Ni 2+ NH 3
NH 3
Fig. 13.8 Tetrahedral shape of [Ni(NH 3
) 4
] 2+ ion resulted from sp 3 hybridisation.
[Zn(NH 3
) 4
] 2+ ; [Ni(Co) 4
] 0 are also the examples of tetrahedral complexes.
Square Planar Complexes
These are formed by dsp 2 hybridisation. Example is [Ni(CN) 4
] –2 . The formation of the
complex is shown below: