Concept of bond length

Question

Which of the following species has the shortest bond length?

a) !!O_2^(-)!!

b) !!O_2^(2-)!!

c) !!O_2^(2+)!!

d) !!O_2^(+)!!

Solution

!!O_2^-, O_2^(2-), O_2^(2+)!! and !!O_2^+!! have bond order !!1.5, 1.0, 3!! and !!2.5!! respectively.

Bond order !!prop 1/"bond length"!!

So, shorest bond length will have maximum bond order.

Therefore !!O_2^(2+)!! will have shorest bond length. Option (c) is correct.