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Answer the following about the coordination compounds.
Write the IUPAC names of the following complexes: (1) (2) (3) With reference to the coordination…
(i)[2.5]
Write the IUPAC names of the following complexes:
(1) $[\text{Cu}(\text{NH}_3)_4]\text{SO}_4$
(2) $[\text{Co}(\text{en})_2\text{Cl}_2]$
(3) $\text{K}_3[\text{Al}(\text{C}_2\text{O}_4)_3]$
(ii)[2.5]
With reference to the coordination complex ion $[\text{Fe}(\text{H}_2\text{O})_6]^{2+}$ answer the following: (at. no. of $\text{Fe} = 26$)
(1) Give the IUPAC name of the complex ion.
(2) What is the oxidation number of the central metal atom?
(3) How many unpaired electrons are there in the complex ion?
(4) State the type of hybridisation of the complex ion.
Answer
Answer (i)
AI1. $[\mathrm{Cu(NH_3)_4}]\mathrm{SO_4}$: tetraamminecopper(II) sulphate
2. $[\mathrm{Co(en)_2Cl_2}]$: dichloridobis(ethane-1,2-diamine)cobalt(II)
3. $\mathrm{K_3[Al(C_2O_4)_3]}$: potassium tris(oxalato)aluminate(III)
Answer (ii)
AI| IUPAC name | hexaaquairon(II) ion |
| Oxidation state | 2 |
| Hybridisation | sp3d2 |
| Unpaired electrons | 4 |
$\mathrm{Fe^{2+}}$ is $3d^6$; $\mathrm{H_2O}$ is a weak field ligand, so no pairing occurs: 4 unpaired electrons, outer orbital ($4s\,4p^3\,4d^2$) $sp^3d^2$ hybridisation, octahedral.
From ISC 2020 Chemistry Paper 1, question 17(a).
Check your working with the Coordination complex analyser: hybridisation, shape, magnetic moment, CFSE, isomers and the IUPAC name of a complex.