QuestionVSEPR / bond lengths
In which of the following molecules/ions, all the bond lengths are NOT equal?
- (a) BF₃
- (b) BF₄⁻
- (c) XeF₄
- (d) SF₄
Answer: (d) SF₄
BF₃ (trigonal planar), BF₄⁻ (tetrahedral), XeF₄ (square planar) have all bonds equivalent. SF₄ is see-saw (sp³d): 2 axial S–F (164.6 pm) are longer than 2 equatorial (154.5 pm) → (d).