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Bond order

Bond order of C₂

Bond order 2, diamagnetic. 12 electrons: Nb = 8, Na = 4.

CC
  • C

C₂Carbon

Bond order 2

12 electrons, all paired

i

Both bonds of the double bond in C2 are pi bonds, as NCERT points out; it is found in the vapour.

  • Bond order2
  • Magnetismdiamagnetic
  • Electrons12

Molecular orbitals

12 electrons
2bond order
diamagnetic

(Nb − Na) / 2 = (8 − 4) / 2

1s1s2s2s2p2pσ1sσ*1sσ2sσ*2sπ2pσ2pzπ*2pσ*2pzC atomMoleculeC atomEnergy

σ1s² σ*1s² σ2s² σ*2s² (π2px² = π2py²)

Working

Bond order step by step

  1. C₂ has 12 electrons: 6 from each C.
  2. Up to N₂ (and its ions), the π2p pair lies below σ2pz and fills first.
  3. Configuration: σ1s² σ*1s² σ2s² σ*2s² (π2px² = π2py²)
  4. Bonding electrons Nb = 8, antibonding electrons Na = 4.
  5. Bond order = (Nb − Na) / 2 = (8 − 4) / 2 = 2.
  6. Every electron is paired, so C₂ is diamagnetic.

Class 11, Chapter 4 Chemical Bonding and Molecular Structure.

Questions

Bond order of C2: quick answers

What is the bond order of C2?

2. Bond order = (Nb − Na) / 2 = (8 − 4) / 2 = 2. Bonding electrons Nb = 8, antibonding electrons Na = 4.

Is C2 paramagnetic or diamagnetic?

Diamagnetic. Every electron is paired, so C₂ is diamagnetic.

What is the molecular orbital configuration of C2?

σ1s² σ*1s² σ2s² σ*2s² (π2px² = π2py²), with 12 electrons in all.

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