Pyramidal shape of trimethylamineट्राइमेथिलऐमीन की पिरैमिडी आकृतिPyramidal shape of trimethylamine

NCERT Fig 9.1 · Class 12 Chemistry · Chapter 9 · interactive diagram

Parts and what they mean

• Nitrogen atom — sp³ hybridised (नाइट्रोजन परमाणु — sp³ संकरित) — Like ammonia, N in amines is trivalent and sp³ hybridised. Three sp³ orbitals overlap with orbitals of C (or H).
• Unshared (lone) pair of electrons (असहभाजित (एकाकी) इलेक्ट्रॉन युग्म) — The fourth sp³ orbital holds the unshared pair. It makes amines basic (Lewis bases) and nucleophilic.
• Fourth sp³ hybrid orbital (चौथा sp³ संकर कक्षक) — Points to the top of the pyramid; it contains the lone pair, not a bond.
• C–N–C bond angle = 108° (C–N–C बंध कोण = 108°) — Less than the tetrahedral 109.5° because the lone pair repels the bond pairs more strongly (NCERT: 108° in trimethylamine).
• Methyl (–CH₃) groups (मेथिल (–CH₃) समूह) — Three H atoms of NH₃ replaced by CH₃ → a tertiary (3°) amine. The wedge one points towards you.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 9.1. Report a mistake