Question

Which one of the following has the regular tetrahedral structure ?

• A. $XeF_4$
• B. $[Ni(CN)+4]^{2-}$
• C. $BF^-_4$
• D. $SF_4$

Answer 1

Answer: (C)

$BF^-_4$

Answer 2

Both $XeF_4$ and $(Ni(CN)_4]^{-2}$ are square planar. In $XeF_4$, Xe is $sp^3\, d^2$ hybridised with 2 lone pairs and Ni in $[Ni(CN)_4]^{2-}$ is $dsp^2$ hybridised. $SF_4$ has a sea-saw shape with S-atom $sp^3d$ - hybridised with one lone pair. $BF_4^-$ has a tetrahedral shape with B-atom $sp^3$ hybridised with no lone pair.