--- title: "Hybridisation, Conjugation and Delocalisation in Organic Molecules" description: "Organic structure has been drawn with lines that all look alike. This stop separates them: how orbitals mix to set geometry, when p orbitals line up to share electrons over several atoms, and what tha" canonical: https://lightmysky.com/learn/science/hybridisation-conjugation-and-delocalisation-in-organic-molecules-mt_Anv0MSQ4hq source: https://lightmysky.com/learn/science/hybridisation-conjugation-and-delocalisation-in-organic-molecules-mt_Anv0MSQ4hq.md retrieved: 2026-09-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Hybridisation, Conjugation and Delocalisation in Organic Molecules Organic structure has been drawn with lines that all look alike. This stop separates them: how orbitals mix to set geometry, when p orbitals line up to share electrons over several atoms, and what that sharing does to length, strength and reactivity. Subject: Science · Area: Chemistry · Ages 18 to 19 Page: https://lightmysky.com/learn/science/hybridisation-conjugation-and-delocalisation-in-organic-molecules-mt_Anv0MSQ4hq ## Ready when they can - Assigns hybridisation at each carbon, nitrogen and oxygen in a drawn structure and predicts the bond angles - Identifies a conjugated system and explains why the arrangement has to be planar to work - Draws the significant resonance forms of an anion and ranks them by stability with reasons - Uses delocalisation to explain a measured bond length that lies between single and double ## Lesson: Hybrids set shape, sharing sets character Carbon remixes its orbitals to fit the bonds it wants. One s plus three p orbitals blend into four sp3 hybrids at tetrahedron corners, giving single bonds near 109.5 degrees. One s with two p gives three flat sp2 hybrids plus one leftover p for a pi bond, hence 120 degrees. One s with one p gives two straight sp hybrids, hence ethyne. Count sigma partners to assign: four means sp3, three means sp2, two means sp. Nitrogen and oxygen play the same game, with lone pairs taking slots and squeezing angles slightly. Conjugation is alternating double and single bonds that let pi electrons roam the whole chain. Pi overlap demands parallel p orbitals, which locks the chain flat and blocks twisting. Twist one link and the pi chain snaps. Long roaming runs absorb visible light, which is why beta carotene makes carrots orange, and longer runs absorb longer wavelengths. **Example.** Some molecules need a team of drawings, called resonance forms, that differ only in electron positions. Rank anion forms by stability: full octets win, and negative charge prefers the more electronegative or better spread home. An amide shows the payoff: the nitrogen lone pair spreads toward the carbonyl oxygen, lending the carbon to nitrogen link partial double character, so it resists rotation. **Tip.** Trust measurements over single drawings. When pi electrons spread over several atoms, bond lengths land between single and double values. Whenever one Lewis drawing keeps lying about a length or a barrier, reach for the delocalised team instead. **Recap.** Hybrids set the geometry, flat p orbitals share the electrons, and the blend explains the measurements. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Benzene: Delocalisation and Electrophilic Substitution](https://lightmysky.com/learn/science/benzene-delocalisation-and-electrophilic-substitution-mt_jFqF7cZ0Ij) - [Naming Organic Compounds and the Formulas That Show Structure](https://lightmysky.com/learn/science/naming-organic-compounds-and-the-formulas-that-show-structure-mt_LCqg41gslT) - [Orbitals, Sub-Shells and Electron Configuration](https://lightmysky.com/learn/science/orbitals-sub-shells-and-electron-configuration-mt_sRMo1f5PfJ) ## Opens up - [Curly Arrows as the Language of Mechanism](https://lightmysky.com/learn/science/curly-arrows-as-the-language-of-mechanism-mt_C0bq2Mu8HT) - [Pericyclic Reactions: The Diels-Alder and Orbital Symmetry](https://lightmysky.com/learn/science/pericyclic-reactions-the-diels-alder-and-orbital-symmetry-mt_I4i9d6aDgD) - [Molecular Symmetry: Elements, Operations and Point Groups](https://lightmysky.com/learn/science/molecular-symmetry-elements-operations-and-point-groups-mt_KcofGO11tm) - [Conformation: Newman Projections and the Chair](https://lightmysky.com/learn/science/conformation-newman-projections-and-the-chair-mt_N0_QpGF7Av)