Bond order is inversely proportional to bond length and directly proportional to bond energy (bond strength). Higher bond order means shorter and stronger bonds. For the oxygen series: O2+ (BO = 2.5, bond length 112 pm), O2 (BO = 2, 121 pm), O2- (BO = 1.5, 126 pm), $O2^{2-}$ (BO = 1, 149 pm). This trend is a favourite JEE question. Similarly for carbon-carbon bonds: C-C (154 pm, 347 kJ/mol), C=C (134 pm, 614 kJ/mol), C triple-bond C (120 pm, 839 kJ/mol). Note that bond energy does not double or triple with bond order because pi bonds are weaker than sigma bonds.