Which of the following are isoelectronic and isostructural? NO−3, CO-23, ClO−3, SO3

Q. Which of the following are isoelectronic and isostructural? NO−3, CO-23, ClO−3, SO3

1. NO−3, CO-23
2. SO3, NO−3
3. ClO−3, CO-23
4. CO-23, ClO−3

Answer: NO−3, CO-23