In which of the following pairs, the two species are isostructural?
- SO32- and NO3-
- BF3 and NF3
- BrO3- and XeO3
- SF4 and XeF4
Answer
(3) BrO3- and XeO3
Solution
Using VSEPR (bond pairs + lone pairs on the central atom):
(1) SO32-: 3 bp + 1 lp ⇒ pyramidal; NO3-: 3 bp + 0 lp ⇒ trigonal planar
(2) BF3: 3 bp + 0 lp ⇒ trigonal planar; NF3: 3 bp + 1 lp ⇒ pyramidal
(3) BrO3-: 3 bp + 1 lp (sp3) ⇒ pyramidal; XeO3: 3 bp + 1 lp (sp3) ⇒ pyramidal
(4) SF4: 4 bp + 1 lp ⇒ see-saw; XeF4: 4 bp + 2 lp ⇒ square planar
∴ BrO3- and XeO3 are isostructural.
Answer: (3)