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Answer the following about the coordination compounds.
Name of the type of isomerism exhibited by the following pairs of compounds: (1) and (2) and (3)…
(i)[2.5]
Name of the type of isomerism exhibited by the following pairs of compounds:
(1) $[\text{Co}(\text{ONO})(\text{NH}_3)_5]^{2+}$ and $[\text{Co}(\text{NO}_2)(\text{NH}_3)_5]^{2+}$
(2) $[\text{Cr}(\text{H}_2\text{O})_4\text{Cl}_2]\text{Cl}\cdot2\text{H}_2\text{O}$ and $[\text{Cr}(\text{H}_2\text{O})_5\text{Cl}]\text{Cl}_2\cdot\text{H}_2\text{O}$
(3) $[\text{Co}(\text{NH}_3)_6][\text{Cr}(\text{CN})_6]$ and $[\text{Cr}(\text{NH}_3)_6][\text{Co}(\text{CN})_6]$
(ii)[2.5]
Using the valence bond approach, predict the shape, hybridisation and magnetic behaviour of $[\text{Ni}(\text{CO})_4]$. (at. no. of $\text{Ni} = 28$)
Answer
Answer (i)
AI1. Linkage isomerism
2. Hydrate (solvate) isomerism
3. Coordination isomerism
Answer (ii)
AI| Hybridisation | sp3 |
| Shape | tetrahedral |
| Magnetic behaviour | diamagnetic |
Ni (0) is $3d^{10}4s^0$ after the $4s$ electrons shift to $3d$; CO is a strong field ligand, so the four CO ligands use one $4s$ and three $4p$ orbitals ($sp^3$), giving a tetrahedral, diamagnetic complex with no unpaired electrons.
From ISC 2020 Chemistry Paper 1, question 17(b).
Check your working with the Coordination complex analyser: hybridisation, shape, magnetic moment, CFSE, isomers and the IUPAC name of a complex.