Question

K2PtCl6 is a well known compound whereas corresponding Ni compound is not known

Answer 1

Platinum is of a large size with vacant orbital which can form complexes of coordination no. 6 however, nickel is of a very small size and cannot hold 6 ligands at a time.

Answer 2

Hey there,

● Answer -
We know K2[Pt(Cl)6] but theoretically similar compound K2[Ni(Cl)6] can't be obtained because -
- Nickel is small size atom and can only form coordination number 4 as compared to platinum which can take upto 6 ligands.
- For similar oxidation state of +4, Ni(IV) is thermodynamically less stable than Pt(IV).

Hope this helps...