The correct bond order in the following species is

Bond order of O22+,O2+and O2-are O22+=σ1s2σ*1s2σ2s2σ*2s2π2px2=π2py2σ2pzπ*2px0=π*2py0    Bond order =10-42=62=3                              O2+=σls2σ*1s2σ2s2σ*2s2σ2pz2π2px2=π2py2π*2px1=π*2py0 Bond order =10-52=52=2.5O2-=σ1s2σ*1s2σ2s2σ*2s2σ2pz2π2px2=π2py2π2px2=π2py1 Bond order =10-72=32=1.5 So, the correct bond order sequence is O22+>O2+>O2-