JEE Challenger
More from Coordination Compounds
ChemMedAdv 2015 • Paper 2

Number of Octahedral Coordination Complexes Exhibiting Cis Trans Isomerism

Out of the following complex ions: [Co(NH2-CH2-CH2-NH2)2Cl2]+[\text{Co}(\text{NH}_2\text{-CH}_2\text{-CH}_2\text{-NH}_2)_2\text{Cl}_2]^+, [CrCl2(C2O4)2]3−[\text{CrCl}_2(\text{C}_2\text{O}_4)_2]^{3-}, [Fe(H2O)4(OH)2]+[\text{Fe}(\text{H}_2\text{O})_4(\text{OH})_2]^+, [Fe(NH3)2(CN)4]−[\text{Fe}(\text{NH}_3)_2(\text{CN})_4]^-, [Co(NH2-CH2-CH2-NH2)2(NH3)Cl]2+[\text{Co}(\text{NH}_2\text{-CH}_2\text{-CH}_2\text{-NH}_2)_2(\text{NH}_3)\text{Cl}]^{2+}, and [Co(NH3)4(H2O)Cl]2+[\text{Co}(\text{NH}_3)_4(\text{H}_2\text{O})\text{Cl}]^{2+}, find the total number of complex ion(s) that exhibit cis-trans isomerism.

Official Numerical Answer6

Topics & Concepts

Coordination CompoundsCoordination CompoundsIsomerism

Step-by-Step Solution

To determine the number of complex ions that exhibit cis-trans isomerism, let us analyze the geometry and coordination type of each octahedral complex ion:

  1. [Co(en)2Cl2]+\left[\text{Co}(\text{en})_2\text{Cl}_2\right]^+:

    • General formula: [M(AA)2a2]\left[\text{M}(\text{AA})_2\text{a}_2\right], where en\text{en} (NH2-CH2-CH2-NH2\text{NH}_2\text{-CH}_2\text{-CH}_2\text{-NH}_2) is a symmetrical bidentate ligand and Cl−\text{Cl}^- is a monodentate ligand.
    • The two chloride ligands can be situated adjacent to each other (90∘90^\circ, cis) or opposite to each other (180∘180^\circ, trans).
    • Exhibits cis-trans isomerism.

  2. [CrCl2(C2O4)2]3−\left[\text{CrCl}_2(\text{C}_2\text{O}_4)_2\right]^{3-}:

    • General formula: [M(AA)2a2]\left[\text{M}(\text{AA})_2\text{a}_2\right], where C2O42−\text{C}_2\text{O}_4^{2-} (oxalate) is a symmetrical bidentate ligand.
    • The two chloride ligands can be situated cis or trans with respect to each other.
    • Exhibits cis-trans isomerism.

  3. [Fe(H2O)4(OH)2]+\left[\text{Fe}(\text{H}_2\text{O})_4(\text{OH})_2\right]^+:

    • General formula: [Ma4b2]\left[\text{Ma}_4\text{b}_2\right].
    • The two hydroxide (OH−\text{OH}^-) ligands can be positioned adjacent (cis) or opposite (trans) to each other.
    • Exhibits cis-trans isomerism.

  4. [Fe(NH3)2(CN)4]−\left[\text{Fe}(\text{NH}_3)_2(\text{CN})_4\right]^-:

    • General formula: [Ma2b4]\left[\text{Ma}_2\text{b}_4\right].
    • The two ammine (NH3\text{NH}_3) ligands can be arranged adjacent (cis) or opposite (trans) to each other.
    • Exhibits cis-trans isomerism.

  5. [Co(en)2(NH3)Cl]2+\left[\text{Co}(\text{en})_2(\text{NH}_3)\text{Cl}\right]^{2+}:

    • General formula: [M(AA)2ab]\left[\text{M}(\text{AA})_2\text{ab}\right].
    • The two different monodentate ligands (NH3\text{NH}_3 and Cl−\text{Cl}^-) can be positioned adjacent (cis) or opposite (trans) to each other.
    • Exhibits cis-trans isomerism.

  6. [Co(NH3)4(H2O)Cl]2+\left[\text{Co}(\text{NH}_3)_4(\text{H}_2\text{O})\text{Cl}\right]^{2+}:

    • General formula: [Ma4bc]\left[\text{Ma}_4\text{bc}\right].
    • The two distinct monodentate ligands (H2O\text{H}_2\text{O} and Cl−\text{Cl}^-) can be positioned adjacent (cis) or opposite (trans) to each other relative to the central metal ion.
    • Exhibits cis-trans isomerism.

Since all 6 complex ions exhibit cis-trans isomerism, the total number of complex ions is 6.

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