Answer:
c. Fe2+
Explanation:
Coordination compounds comprise solely complex ions together with one or more counter ions. They are compounds in which metal atoms or ions are directly bonded to anions or neutral atoms in conjunction with coordinate covalent bonds.
From the given options, only Fe2+ can form both low-spin and high-spin.
To determine that, we find out the number of unpaired spins in Fe2+
At the ground state:
The electronic configuration is:
Fe: [Ar] 3d⁶ 4s²
After the removal of two electrons, the configuration becomes
Fe²⁺ : [Ar] 3d⁶
A metal ion has the ability to form both low-spin and high-spin complexes if the metal-ion comprises more than 3 and less than 8 d -electrons.
So, since Fe²⁺ contains more than 3 and less than 8. Then Fe²⁺ is the right option.
Ti²⁺ contains only two d electrons
Cu⁺ contains more than eight d electrons
Ni²⁺ contains eight d electrons
Cr³⁺ contains three d electrons
