The formula of the complex ethylenetrichloridoplatinum (II) is

Options

A. `K_(3)[Pt_(2)CI_(3)(C_(2)H_(4))_(3)]`
B. `K_(2)[PtCI_(3)(C_(2)H_(4))_(3)]`
C. `K[Pt(C_(2)H_(4))CI_(3)]`
D. `K_(4)[PtCI_(3)(C_(2)H_(4)]`

Answer

C

Explanation

Zeise's salt `K[Pt(C_(2)H_(4))(CI)_(3)].H_(2)O` forms yellow crystals. In Zeise's salt the `[Pt(C_(2)H_(4))CI_(3)]^(-)` complex ion is essentially square planar with CI at three comers and `H_(2)C=CH_(2)` at the other corner. However, the `H_(2)C=CH_(2)` molecule is perpendicular to the `PtCI_(3)` plane and the two C atoms are almost equidistant form the Pt. The Pt-C distances are `2.128 Å` and `2.135 Å` . The `C=C` distance in the complex is `1.375 Å` compared with `1.337 Å` in ethene and a C-C distance of `1.54 Å` in ethane. Thus the double bond is only lengthened slightly in forming the complex. The double bound occupies the coordination position rather than a single C atom, and thus `C_(2)H_(4)` as a dihapto ligand. Thus, the complex should be written `K[Pt(eta^(2)-C_(2)H_(4)) (CI_(3)).]H_(2)O` .