Despite the fact that atomic radius generally increases down a group, the Pd-Cl distance in PdCl42- is essentially identical to

Question

Despite the fact that atomic radius generally increases down a group,
the Pd-Cl distance in PdCl42- is essentially identical to the Pt-Cl
distance in PtCl42. Which is the best explanation of why the two bond
lengths are the same?
PdCl42- is tetrahedral, while PtCl42- is square planar, and so shorter bonds
are expected.
The presence of the 14 lanthanides between Pd and Pt makes Pt
unexpectedly small
The large negative charge on the complex ions makes the chloride-chloride
repulsions, not the metal-chloride attractions, the dominant factor in
determining the bond distance
The Pd-Cl bond is largely ionic, whereas the Pt-Cl is largely covalent, and so
the atoms necessarily have to be closer together to form a covalent bond
The metal-chlorine bonds are highly covalent and are insensitive to the trend
in atomic radius

Kunduz · Accepted Answer

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