CBSE Class 12 · 2009 · Delhi · Coordination CompoundsShort Answer

For the complex [Fe(en)

_{2}

_{2}

]Cl (en = ethylenediamine), identify:
i) the oxidation number of iron
ii) the hybrid orbitals and the shape of the complex
iii) the magnetic behaviour of the complex
iv) the number of geometrical isomers
v) whether there is an optical isomer also
vi) the name of the complex. (Atomic number of Fe = 26)

Solution

(i) x + 0 + 2(−1) = +1 ⇒ \textbf{Fe = +3} (3d

^{5}

).
(ii) en is a strong-field chelating ligand → pairing; \textbf{d

^{2}

^{3}

, octahedral}.
(iii) Low-spin 3d

^{5}

= t

_{2 g}^{5}

: \textbf{1 unpaired electron — paramagnetic} (μ ≈ 1.73 BM).
(iv) M(AA)

_{2}

_{2}

gives \textbf{2 geometrical isomers} — cis and trans.
(v) \textbf{Yes}: the cis form lacks a symmetry plane and exists as d/l optical isomers.
(vi) \textbf{Dichloridobis(ethane-1,2-diamine)iron(III) chloride}.

CBSE Class 12 Board · 2009 · Delhi · Subjective

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CBSE Class 12 · 2009 · Delhi · Coordination CompoundsShort Answer

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