Question

Arrange the following molecules in decreasing bond length.

(a) O2  > O2^–  > O2^+  > O2^2-

(b) O2^2- > O2^–  > O2 > O2^+

(c) O2^2-  > O2^–  > O2^+  > O2

(d) O2^–  > O2^+  > O2^2-  > O2

I have been asked this question during an interview.

This intriguing question originated from Molecular Orbital Theory in portion Atoms to Molecules to Material’s for Engineers of Engineering Chemistry I

Answer 1

Correct choice is (b) O2^2- > O2^–  > O2 > O2^+

To explain I would say: The bond length is inversely proportional to the bond order. Therefore, the correct is:

O2^2-  > O2^–  > O2  > O2^+.