Question

Which of the following species is not stable?

• A. $[Si{F}_6{]}^{2-}$
• B. $[GeC{l}_6{]}^{2-}$
• C. $\left[Sn\right(OH{)}_6{]}^{2-}$
• D. $[SiC{l}_6{]}^{2-}$

Answer 1

The correct option is D $[SiC{l}_6{]}^{2-}$

Due to the presence of d-orbitals in $Si,Ge$ and $Sn$ they form species like $[Si{F}_6{]}^{2-}$, $[GeC{l}_6{]}^{2-}$, $\left[Sn\right(OH{)}_6^{2-}]$.

$[SiC{l}_6{]}^{2-}$ does not exist because six chloride ions cannot be accomadated around $S{i}^{4+}$ due to its smaller size. The repulsion between the chloride ions will be more which makes $[SiC{l}_6{]}^{2-}$ unstable.