Given below are two statements : Statement I: Both [ Co ( NH _3 )_6 ]^ 3+ and [ CoF _6 ]^ 3- complexes are octahedral but differ in their magnetic behaviour. Statement II: [ Co ( NH _3 )_6 ]^ 3+ is diamagnetic whereas [ CoF _6 ]^ 3- is paramagnetic. In the light of the above statements, choose the correct answer from the options given below:
D. Both Statement I and Statement II are true
In [ Co ( NH _3 )_6 ]^ 3+ , Co ^ 3+ ion is having 3 ~d ^6 configuration. Electronic configuration of Co ^ 3+ : In presence of NH _3 ligand, pairing of electrons takes place and it becomes diamagnetic complex ion. In presence of NH _3 ligand : [ Co ( NH _3 )_6 ]^ 3+ is octahedral with d ^2 sp ^3 hybridisation and it is diamagnetic in nature. In case of [ CoF _6 ]^ 3- , Co is in +3 oxidation state and it is having 3 ~d ^6 configuration. In presence of weak field F ^ - ligand, pairing does not take place. In presence of F ^ - ligands : In [ CoF _6 ]^ 3- , Co ^ 3+ is sp ^3 ~d ^2 hybridised with four unpaired electrons, so it is paramagnetic in nature.
Related: Chemistry — Coordination Compounds · All PYQ Banks