Question

For the given coordination compounds:
1) \([Co(ox)_3]^{3-}\) 2) \([Fe(CN)_6]^{3-}\) 3) \([Ni(CN)_4]^{2-}\) 4) \([NiCl_4]^{2-}\)
5) \([Ni(CO)_4]\) 6) \([MnBr_4]^{2-}\) 7) \([CoF_6]^{3-}\) 8) \([Cr(H_2O)_3F_3]\)
The number of paramagnetic species are:

Answer 1

Correct Answer: 3

We need to identify the paramagnetic species based on the number of unpaired electrons in the metal center. The species that have unpaired electrons are paramagnetic. 1) \([Co(ox)_3]^{3-}\): Cobalt in \( +3 \) oxidation state (\(d^6\)) – Low spin complex, no unpaired electrons, hence diamagnetic.
2) \([Fe(CN)_6]^{3-}\): Iron in \( +3 \) oxidation state (\(d^5\)) – Paramagnetic with 5 unpaired electrons. 3) \([Ni(CN)_4]^{2-}\): Nickel in \( +2 \) oxidation state (\(d^8\)) – Diamagnetic.
4) \([NiCl_4]^{2-}\): Nickel in \( +2 \) oxidation state (\(d^8\)) – Diamagnetic.
5) \([Ni(CO)_4]\): Nickel in \( 0 \) oxidation state (\(d^10\)) – Diamagnetic.
6) \([MnBr_4]^{2-}\): Manganese in \( +2 \) oxidation state (\(d^5\)) – Paramagnetic with 5 unpaired electrons.
7) \([CoF_6]^{3-}\): Cobalt in \( +3 \) oxidation state (\(d^6\)) – Low spin complex, no unpaired electrons, hence diamagnetic.
8) \([Cr(H_2O)_3F_3]\): Chromium in \( +3 \) oxidation state (\(d^3\)) – Paramagnetic with 3 unpaired electrons.

Step 1: Identify the paramagnetic species.
Paramagnetic species: \([Fe(CN)_6]^{3-}\), \([MnBr_4]^{2-}\), \([Cr(H_2O)_3F_3]\).
Step 2: Count the number of paramagnetic species.
There are 3 paramagnetic species.