Bond order and magnetic behaviour from MOT
Advanced Chemical Bonding · Chemistry
Study notes
O₂⁺, O₂, O₂⁻, O₂²⁻: arrange by bond length. Step 1: Count valence e⁻: O₂⁺ 11, O₂ 12, O₂⁻ 13, O₂²⁻ 14. Step 2: Fill π*2p: O₂⁺ has 1 π* electron (BO 2.5), O₂ has 2 (BO 2), O₂⁻ has 3 (BO 1.5), O₂²⁻ has 4 (BO 1). Step 3: Higher BO = shorter bond: O₂⁺ < O₂ < O₂⁻ < O₂²⁻. Step 4: Matches measured lengths: 112, 121, 128, 149 pm!