Limiting radius ratio I recently came across this question while studying Solid State.
The coordination no. of [Ni(CN)4]2- is 4  as Ni is bonded to 4 CNs and  is planar in structure.Hence its Limiting Radius Ratio must be between 0.225 and 0.414 . But the answer given in the book is 0.414 to 0.732 (which is the limiting radius ratio for coordination no. 6) .
How is this true?Some sites agree with my answer .
Is the answer given in the book wrong or have I made any mistake in the reasoning?
Here, limiting radius ratio is for geometry of this complex is square planar because $\ce{CN-}$ is a strong field ligand and causes pairing of unpaired electrons. So we can relate that $\ce{Ni^2+}$  occupies a square planar void of the $\ce{CN-}$ lattice. The square planar void is a cross section of the octahedral void.