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Delocalized Electrons: Resonance. When writing Lewis structures for species like the nitrate ion, we draw resonance structures to more accurately reflect the structure of the molecule or ion. Delocalized Electrons: Resonance.
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Delocalized Electrons: Resonance When writing Lewis structures for species like the nitrate ion, we draw resonance structures to more accurately reflect the structure of the molecule or ion.
Delocalized Electrons: Resonance • In reality, each of the four atoms in the nitrate ion has a p orbital. • The p orbitals on all three oxygens overlap with the p orbital on the central nitrogen.
Delocalized Electrons: Resonance This means the electrons are not localized between the nitrogen and one of the oxygens, but rather are delocalized throughout the ion.
Benzene’s Unusual Structure • All its C-C bonds are the same length: 139 pm — between single (154 pm) and double (134 pm) bonds • Electron density in all six C-C bonds is identical • Structure is planar, hexagonal • C–C–C bond angles 120° • Each C is sp2 and has a p orbital perpendicular to the plane of the six-membered ring
Delocalized Electrons and Resonance Chapter 7
Bonding in Benzene (a) Carbon–carbon and carbon–hydrogen s bonds (b) Carbon p-orbitals overlap with neighbors (c) Cloud of p electrons above and below ring (d) Electrostatic potential map for benzene Chapter 7
Drawing Benzene and Its Derivatives • The two benzene resonance forms can be represented by a single structure with a circle in the center to indicate the equivalence of the carbon–carbon bonds • This does not indicate the number of electrons in the ring but reminds us of the delocalized structure
Sigma Bonds: Hybrid Orbitals, Localized Electrons Pi Bonds: Molecular Orbitals, Delocalized Electrons