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Answer the following.
Answer the following: For the complex compound , identify the following: (1) Oxidation state (2)…
Answer the following:
(a)[2.0]
For the complex compound $[\text{Fe}(\text{en})_2\text{Cl}_2]\text{Cl}$, identify the following:
(1) Oxidation state
(2) Hybridisation of the central metal atom
(3) Magnetic behaviour of the complex
(4) Geometry of the complex
(b)[2.0]
Draw the structures of geometrical isomers of complex $[\text{Pt}(\text{en})_2\text{Cl}_2]^{2+}$.
Draw: Geometrical isomers of complex [Pt(en)2Cl2]2+
(c)[1.0]
On the basis of crystal field theory, write the electronic configuration for $d^4$ ion in octahedral crystal field, if $\Delta_o > P$.
Answer
Answer (a)
Official answer key| Oxidation state | +3 |
| Hybridisation | d2sp3 |
| Shape | octahedral |
| Magnetic behaviour | paramagnetic |
Oxidation state: $x + 0 + 2(-1) + (-1) = 0$ for $[\mathrm{Fe(en)_2Cl_2}]\mathrm{Cl}$, so Fe is +3 ($3d^5$). With six donor atoms the hybridisation is $d^2sp^3$ (inner orbital), one unpaired electron remains, so it is paramagnetic, and the geometry is octahedral.
Answer (b)
Official answer key$[\mathrm{Pt(en)_2Cl_2}]^{2+}$ is octahedral and has two geometrical isomers: trans (two Cl on opposite positions, along one axis, with the two en in the plane) and cis (two Cl adjacent, at 90 degrees). Both drawn inside square brackets with charge 2+.
Answer (c)
Official answer keyFor $d^4$ with $\Delta_o > P$ (strong field, low spin) the electrons pair up in the lower set: configuration $t_{2g}^4 e_g^0$.
From ISC 2026 Specimen Chemistry Paper 1, question 21(ii).
Check your working with the Coordination complex analyser: hybridisation, shape, magnetic moment, CFSE, isomers and the IUPAC name of a complex.