Question

The structure of $K[PtC{l_3}({C_2}{H_4})]$ and the hybridization of Pt respectively are:
A.square planar, $s{p^2}{d^2}$
B.Square planar, $ds{p^2}$
C.Tetrahedral, $s{p^3}$
D.Octahedral, ${d^2}s{p^3}$

Answer 1

This given compound is more commonly known as Zeise’s Salt and is chemically named as potassium trichloro(ethylene)platinate (II). Potassium is the cationic part of this salt, while ${[PtC{l_3}({C_2}{H_4})]^ - }$ is the anionic part.

Complete step by step answer:
The given compound is a salt made of an anion and a cation. This salt is of historic significance in organometallic chemistry because it is one of the first known examples of transition metal alkene complexes. The anionic part of the salt is a coordination complex which is yellow in colour, stable in air and contains a ${\eta ^2} - ethylene$ ligand. The ${\eta ^2}$ structure corresponds to the metal alkene system.
Pi ligands are basically a type of organometallic ligands which have extended $\pi$ systems, which include linear molecules like ethylene, allyl and cyclic molecules. Because of this, we can say that the given compound is a $\pi$ complex.
Potassium is the central atom here and has 4 different ligands that are attached to it. This gives the entire compound a square planar geometry and thus the platinum in this salt undergoes hybridization$ds{p^2}$.

Hence, Option B is the correct option.

Note:
The ‘σ-bond’ produced from donation of ‘π-electron’ clouds of alkene to the metal centre is called ‘μ-bond’. Bonding takes place as—
${C_2}{H_4}$ (π)→Pt ($ds{p^2}$) μ type σ-bond
Pt (‘dxz’ or ‘dp’ hybrid) →${C_2}{H_4}$ (π*) π bond