The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are)\ (Note : py = pyridine G

Question

The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are)\ (Note : py = pyridine Given : Atomic numbers of $\mathrm{Fe}, \mathrm{Co}, \mathrm{Ni}$ and Cu are 26, 27, 28 and 29 , respectively)\

Professor PC Thomas Classes · Answer

(a, b, d) : $\left[\mathrm{FeCl}_{4}ight]^{-} \Rightarrow \mathrm{Fe}^{3+}$\ $\mathrm{Fe}^{3+}:[\mathrm{Ar}] 3 d^{5}$\ $\mathrm{Cl}^{-}$is a weak ligand so no pairing will take place, hybridisation : $s p^{3}$;\ geometry : tetrahedral\ $\left[\mathrm{Fe}(\mathrm{CO})_{4}ight]^{2-}$ :\ Fe: $[\mathrm{Ar}] 3 d^{6} 4 s^{2}$\ $\mathrm{Fe}^{2-}:[\mathrm{Ar}] 3 d^{8} 4 s^{2}$\ $\mathrm{Fe}^{2-}\left(d^{10}ight)$ in $\left[\mathrm{Fe}(\mathrm{CO})_{4}ight]^{2-}$ :\ Co: [Ar] $3 d^{7} 4 s^{2}$\ $\mathrm{Co}^{-}:[\mathrm{Ar}] 3 d^{8} 4 s^{2}$\ $\mathrm{Co}^{-}$in $\left[\mathrm{Co}(\mathrm{CO})_{4}ight]^{-}$:\ \ $\mathrm{Co}^{2+}:[\mathrm{Ar}] 3 d^{7}$\ $\mathrm{Cl}^{-}$is a weak field ligand, so no pairing will take place.\ $\mathrm{Co}^{2+}$ in $\left[\mathrm{CoCl}_{4}ight]^{2-}$ :\ \ $\mathrm{Ni}(28):[\mathrm{Ar}] 3 d^{8} 4 s^{2}$\ Ni in $\left[\mathrm{Ni}(\mathrm{CO})_{4}ight]:$\ \ $\mathrm{Ni}(28):[\mathrm{Ar}] 3 d^{8} 4 s^{2}$\ $\mathrm{Ni}^{2+}:[\mathrm{Ar}] 3 d^{8}$\ $\mathrm{Ni}^{2+}$ in $\left[\mathrm{Ni}(\mathrm{CN})_{4}ight]^{2-}$ :\ \ $\left[\mathrm{Cu}(p y)_{4}ight]^{+}: \mathrm{Cu}:[\mathrm{Ar}] 3 d^{10} 4 s^{1}$\ $\mathrm{Cu}^{+}:[\mathrm{Ar}] 3 d^{10}$\ $\mathrm{Cu}^{+}$in $\left[\mathrm{Cu}(\mathrm{py})_{4}ight]^{+}$:\ \ $\left[\mathrm{Cu}(\mathrm{CN})_{4}ight]^{3--}: \mathrm{Cu}^{+}:[\mathrm{Ar}] 3 d^{10}$\ $\mathrm{Cu}^{+}$in $\left[\mathrm{Cu}(\mathrm{CN})_{4}ight]^{3-}$ :\ \