COMEDK Exam 2018 Solved Paper

In [CoF6]3−,F−is a weak ligand. It cannot pair up d-electrons and form outer orbital octahedral complex while NH3 and CN−are strong ligand.
In [CoF6]3−, outer orbital 4d is used in hybridisation.
Thus, it is called outer orbital or high spin or spin free complex.
Co=[Ar]3d74s2‌ and ‌Co3+=[Ar]3d6