Question

Consider the following complex, $\left[Co\right(N{H}_3{)}_{5}C{O}_3]Cl{O}_4$ the coordination number, oxidation number, number of $d$ - electrons and number of unpaired $d$ - electrons of the metal are respectively :

• A. $6,3,6,0$
• B. $7,2,7,1$
• C. $7,1,6,4$
• D. $6,2,7,3$

Answer 1

The correct option is A $6,3,6,0$

Consider the following complex :

$\left[Co\right(N{H}_3{)}_{5}C{O}_3]Cl{O}_4$ the coordination number, oxidation number, number of $d$ - electrons and number of unpaired $d$ - electrons of the metal are respectively $6,3,6,0$

5 ammonia ligands and one carbonate ligand is present. Hence, the coordination number is 6.

Let X be the oxidation number of Co.

$X+5\left(0\right)+(-2-1)=0$

$X=+3$

Co(III) has $3d^6$ as outer electronic configuration.

Hence, the number of d electrons are 6.

All the 6 d electrons are present in $t_{2g}$ level.

Hence, the number of unpaired d electrons is zero.