Draw the structures of geometrical isomers of the following coordination complexes:
[Co(NH3)3Cl3] and [CoCl2(en)2+]
(en = ethylene diamine and atomic number of Co is 27).
(a) sp3 hybrid orbitals: This type of hybridization explains the tetrahedral geometry of complexes such as Ni(CO)4 and [Zn(NH3)4]2+.
(b) dsp2 hybrid orbitals: These hybrid orbitals attain square planar shape, dsp2 hybrid orbitals are involved in the bonding of the complexes such as [Ni(CN)4] and [Pt(NH3)4]2+.
(c) d2sp3 hybrid orbitals: These hybrid orbitals attain octahedral shape and explain the bonding in the complexes such as [Co(NH3)6]3+ and [Fe(CN)6]3–.
(i) Explain geometrical isomerism with reference to square planar complexes giving one example. How is tetrahedral complexes with simple ligands do not exhibit geometrical isomerism?
(ii) Using valence bond theory, predict the shape and magnetism (paramagnetism) or diamagnetism of [Co(CO)4]– (at. no. of Co = 27)?
(iii) How is stability of coordination compounds determined in aqueous solution?