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 why

K_{4} [Fe {(CN)}_{6}]

is diamagnetic while

K_{3} [Fe {(CN)}_{6}]

is paramagnetic.

Accepted Answer

In the complex $K_{4} [Fe {(CN)}_{6}]$ , the oxidation number of ${Fe}^{+ 2}$ . According to Hund's rule, the number of unpaired electrons in $3 d$ -subshell of ${}_{26}{Fe} [({}_{18}{Ar}) 3 d^{6} 4 s^{2}]$ are four while in ${Fe}^{2 +}$ ion $[({}_{18}{Ar}) 3 d^{6} 4 s^{0}]$ , there are also four unpaired electrons. In order to accommodate 6 electron pairs donate by six ${CN}^{-}$ ligands, six vacant hybrid orbitals $d^{2} {sp}^{3}$ (using outer 4d orbitals) must be made available. As there are no unpaired electrons present, the compound is diamagnetic.

In $K_{3} [Fe {(CN)}_{6}]$ complex, the oxidation number of $Fe = + 3$ . According to Hund's rule, the number of unpaired electrons in $3 d$ -subshell of ${}_{26}{Fe} [({}_{18}{Ar}) 3 d^{6} 4 s^{2}]$ are four while in ${Fe}^{3 +}$ ion $[({}_{18}{Ar}) 3 d^{5} 4 s^{0}]$ there are five unpaired electrons. In order to accommodate six electron pairs donated by six ${CN}^{-}$ ligands, six vacant hybrid orbitals, $d^{2} {sp}^{3}$ (using inner $3 d$ -orbitals) must be made available. Due to the presence of unpaired electron, it is a paramagnetic compound.

Therefore, $K_{4} [Fe {(CN)}_{6}]$ is diamagnetic while $K_{3} [Fe {(CN)}_{6}]$ is paramagnetic.

Explain why $K_{4} [Fe {(CN)}_{6}]$ is diamagnetic while $K_{3} [Fe {(CN)}_{6}]$ is paramagnetic.

Important Questions on Coordination Compounds

Learn and Prepare for any exam you want !

Explain why K4FeCN6 is diamagnetic while K3FeCN6 is paramagnetic.

Important Questions on Coordination Compounds

Learn and Prepare for any exam you want !

Explain why $K_{4} [Fe {(CN)}_{6}]$ is diamagnetic while $K_{3} [Fe {(CN)}_{6}]$ is paramagnetic.