Name: Nomenclature of Coordination Compounds - I
Uploaded: 2019-07-19
Duration: 7 min 4 s
Description: All the chemical compounds are assigned a name, which is done according to a specific rule. How are coordination compounds named? Let’s watch the video to fi...

Question

Explain

{[Co {({NH}_{3})}_{6}]}^{3 +}

is an inner orbital complex whereas

{[Ni {({NH}_{3})}_{6}]}^{2 +}

is an outer orbital complex.

Accepted Answer

When the complex formed involves the use of outer $n$ $d -$ orbitals for hybridization $({sp}^{3} d^{2})$ , the complex is called the outer orbital complex. When the complex formed involves the inner $(n - 1) d -$ orbitals for hybridization $(d^{2} {sp}^{3})$ , the complex is called the inner orbital complex. Among the given complexes, ${[Co {({NH}_{3})}_{6}]}^{3 +}$ involves inner $(n - 1)$ $d -$ orbitals. Therefore, it is called the inner orbital complex. Whereas, ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ involves $n d -$ orbitals. Therefore, it is an outer orbital complex.
In ${[Co {({NH}_{3})}_{6}]}^{3 +}$ complex, the oxidation number of $Co = + 3$ . According to Hund's rule, the number of unpaired electrons in 3d-subshell of ${}_{27}{Co} [({}_{18}{Ar}) 3 d^{7} 4 s^{2}]$ is three while in ${Co}^{3 +}$ ion $[({}_{18}{Ar}) 3 d^{6}]$ there are four unpaired electrons.

Whereas, in the case of ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ , the electronic configuration of ${}_{28}{Ni} [(Ar) 3 d^{8} 4 s^{2}]$ and that of ${Ni}^{2 +}$ is $[(Ar) 3 d^{8} 4 s^{0}]$ . In the complex $({NH}_{3})$ is a strong field ligand but if pairing occurs only one $d -$ orbital will be available so it cannot undergo $d^{2} {sp}^{3}$ hybridization.

$3 d 4 s 4 p 4 d Ni - atom ⥮ ⥮ ⥮ ↑ ↑ ⥮ {Ni}^{+ 2} (II) ⥮ ⥮ ⥮ ↑ ↑ {[Ni {({NH}_{3})}_{6}]}^{2 +} ⥮ ⥮ ⥮ ↑ ↑ \underset{{NH}_{3}}{* *} \underset{{NH}_{3}}{* *} \underset{{NH}_{3}}{* *} \underset{{NH}_{3}}{* *} \underset{{NH}_{3}}{* *} \underset{{NH}_{3}}{* *}$

Explain ${[Co {({NH}_{3})}_{6}]}^{3 +}$ is an inner orbital complex whereas ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ is an outer orbital complex.

Important Questions on Coordination Compounds

Learn and Prepare for any exam you want !

Explain Co(NH3)63+ is an inner orbital complex whereas Ni(NH3)62+ is an outer orbital complex.

Important Questions on Coordination Compounds

Learn and Prepare for any exam you want !

Explain ${[Co {({NH}_{3})}_{6}]}^{3 +}$ is an inner orbital complex whereas ${[Ni {({NH}_{3})}_{6}]}^{2 +}$ is an outer orbital complex.