Orbital diagram for the formation of the carbonyl groupकार्बोनिल समूह के बनने का कक्षक आरेखOrbital diagram for the formation of the carbonyl group
NCERT Fig 8.1 · Class 12 Chemistry · Chapter 8 · interactive diagram
Parts and what they mean
- Carbonyl carbon — sp² hybridised (कार्बोनिल कार्बन — sp² संकरित) — Uses three sp² hybrid orbitals to form three σ bonds; its fourth electron stays in an unhybridised p orbital.
- Carbonyl oxygen (कार्बोनिल ऑक्सीजन) — Forms one σ bond and one π bond with carbon; more electronegative, so the C=O bond is polar.
- σ bonds of the carbonyl carbon (कार्बोनिल कार्बन के σ बंध) — Three σ bonds (to O, R and R′) lie in ONE plane — trigonal coplanar.
- Bond angles ≈ 120° (बंध कोण ≈ 120°) — As expected for a trigonal coplanar (sp²) carbon.
- Unhybridised p orbital of carbon (कार्बन का असंकरित p कक्षक) — Perpendicular to the molecular plane; overlaps sideways with the p orbital of O.
- p orbital of oxygen (ऑक्सीजन का p कक्षक) — Overlaps sideways with the p orbital of C to form the π bond.
- π bond — electron cloud above and below the plane (π बंध — तल के ऊपर और नीचे इलेक्ट्रॉन मेघ) — This is why a nucleophile attacks the carbonyl carbon from roughly perpendicular to the plane.
- Two non-bonding electron pairs on O (O पर दो अबंधी इलेक्ट्रॉन युग्म) — Make the oxygen a nucleophilic (Lewis base) centre — e.g. it gets protonated by acids.
- R group (alkyl/aryl or H) (R समूह (ऐल्किल/ऐरिल या H)) — For an aldehyde one of the two groups is H.
- R′ group (R′ समूह) — For a ketone both groups are carbon groups.
- The molecular plane (अणु तल) — The carbonyl carbon and the three atoms attached to it lie in this plane.
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 8.1. Report a mistake