Ammonia

NH₃ is a strong field ligand

Total Number of electrons : 6

To find the number of species/ions with an identical bond order using Molecular Orbital (MO) theory, we need to calculate the bond order for each given species using the formula: Bond Order = (Number of bonding electrons - Number of antibonding electrons) / 2.

• CN^-:
  The electronic configuration is (σ_1s)²(σ_1s*)²(σ_2s)²(σ_2s*)²(π_2p)⁴(σ_2p)².
  Bonding electrons: 10, Antibonding electrons: 4.
  Bond Order = (10 - 4) / 2 = 3.
• NO⁺:
  The electronic configuration is (σ_1s)²(σ_1s*)²(σ_2s)²(σ_2s*)²(π_2p)⁴(σ_2p)².
  Bonding electrons: 10, Antibonding electrons: 4.
  Bond Order = (10 - 4) / 2 = 3.
• O₂:
  The electronic configuration is (σ_1s)²(σ_1s*)²(σ_2s)²(σ_2s*)²(π_2p)⁴(π_2p*)².
  Bonding electrons: 10, Antibonding electrons: 6.
  Bond Order = (10 - 6) / 2 = 2.
• O₂⁺:
  The electronic configuration is (σ_1s)²(σ_1s*)²(σ_2s)²(σ_2s*)²(π_2p)⁴(π_2p*)¹.
  Bonding electrons: 10, Antibonding electrons: 5.
  Bond Order = (10 - 5) / 2 = 2.5.
• O₂²⁺:
  The electronic configuration is (σ_1s)²(σ_1s*)²(σ_2s)²(σ_2s*)²(π_2p)⁴.
  Bonding electrons: 10, Antibonding electrons: 4.
  Bond Order = (10 - 4) / 2 = 3.

Species with identical bond order of 3: CN^-, NO⁺, O₂²⁺.
Number of such species = 3, which fits within the provided range (3,3).