Q23.87P - Chemistry: Molecular Nature Of Matter And Change

Question

Is a complex with the same number of unpaired electrons as the free gaseous metal ion termed high spin or low spin?

Step-by-Step Solution

Answer

The complex with the same number of unpaired electrons as the free metal ion is termed a high-spin complex.

Step 1: The concept of magnetic properties is used

The magnetic properties of metal complexes rise from the energy splitting of metal ion's d orbitals and these magnetic properties are based on the number of unpaired electrons in d orbitals

Step 2: Detailed explanation

The complex with the same number of unpaired electrons as the free metal ion is termed a high-spin complex.

The magnetic properties of metal complexes rise from the energy splitting of metal ion's d orbitals and these magnetic properties are based on the number of unpaired electrons in d orbitals. The occupancy of d orbitals depends on pairing energy $\left({\mathrm{E}}_{\mathrm{pairing}}\right)$ and crystal field splitting energy $\left(\Delta \right)$. The complex with the same number of unpaired electrons as the free metal ion is termed as high-spin complex and it has the maximum number of unpaired electrons. High-spin complexes occur when weak-field ligands bond with central metal ion because they cause small splitting energy; in this case  ${\mathrm{E}}_{\mathrm{pairing}}>∆$.