Bond order (BO) Number of Bonding electrons =2−Number of non - bonding electrons​ Total number of electrons in CN⊖ ions =6+7+1=14 MO configuration of CN⊖ ion =σ1s2,σ∗1s2,σ2s2,σ∗2s2,π2px2​≈π2py2​,σ2pz2​ and number of bonding electrons =10 Number of non-bonding Electrons =4∴B.O.=210−4​=3