Orbitals of Co ion
3+
sp d
3
2
3+
hybridised
orbitals of Co
[CoF ]
(outer orbital or
high spin complex)
6
3–
Six pairs of electrons
from six F ions
–
3d
4s
4p
sp d
3
3 hybrid
4d
3d
3d
Six pairs of electrons, one from each NH3 molecule, occupy the six
hybrid orbitals Thus, the complex has octahedral geometry and is
diamagnetic because of the absence of unpaired electron In the formation
of this complex, since the inner d orbital (3d) is used in hybridisation,
the complex, [Co(NH3)6]
3+ is called an inner orbital or low spin or spin
paired complex The paramagnetic octahedral complex, [CoF6]
3– uses
outer orbital (4d ) in hybridisation (sp
3d
2)