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Hybridized Orbitals

Hybridized Orbitals. V-B theory can’t explain some observations about molecular compounds without the concept of hybridized orbitals. i.e., covalent (NM/NM) compounds. …the result then being…. …the central atom SHOULD be…. …but is ACTUALLY hybridized to be…. (LS). In….

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Hybridized Orbitals

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  1. Hybridized Orbitals V-B theory can’t explain some observations about molecular compounds without the concept of hybridized orbitals. i.e., covalent (NM/NM) compounds

  2. …the result then being… …the central atom SHOULD be… …but is ACTUALLY hybridized to be… (LS) In… 2 hyb. sp orbs. 2 unhyb. 2p orbs. BeF2 2s 2p sp 2p 3 hyb. sp2 orbs. 1 unhyb. 2p orb. BF3 2s 2p 2p sp2 CH4 4 hyb. sp3 orbs. 2s 2p sp3 : : : F : : : : : F Xe F : : H2O : 4 hyb. sp3 orbs. : : : : : F : : : P F F F : 2s 2p sp3 : : : H : : : 5 hyb. sp3d orbs. 4 unhyb. 3d orbs. : : : F F B F PF5 H C H : : : : : : : : : F Xe F : : H : 3s 3p 3d 3d : : sp3d : : : F F : H O : : : : H : : F Be F : : 5 hyb. sp3d orbs. 4 unhyb. 5d orbs. XeF2 5s 5p 5d 5d sp3d 6 hyb. sp3d2 orbs. 3 unhyb. 5d orbs. XeF4 5s 5p 5d 5d sp3d2

  3. KEY: EDG  hybridization of central atom linear  sp trig. planar  sp2 tetrahedral  sp3 trig. bipyr.  sp3d octahedral  sp3d2

  4. sp hybridization sp hybridization occurs when one s and one of the three p orbitals hybridize. It results in the creation of two sp hybrid orbitals (orange). The other two p orbitals (purple) are unhybridized; they retain the “figure-8” or “dumbbell” shape.

  5. The bonds in ammonia are s bonds. .. N H H H Multiple Bonds s (sigma) bonds are bonds in which the e– density is along the internuclear axis. -- These are the single bonds we have considered up to this point. -- e.g., s-s, s-p, or p-p overlap, and also p-sp hybrid overlap sigma (s) = single Multiple bonds result from the overlap of two p orbitals (one from each atom) that are oriented perpendicularly to the internuclear axis. These are p (pi) bonds. pi, multiple, unhybridized

  6. H H – – C=C – – H H H H C C H H p bonds are generally weaker than s bonds because p bonds have less overlap. For ethene (C2H4)… For each carbon atom, there are 3 sp2 hybridized orbitals; these form s bonds (- - - -) with C or H. Where unhybridized orbitals overlap, a p bond ( ) is formed.

  7. Single bonds are s bonds. e.g., C2H6 Double bonds consist of one s and one p. e.g., C2H4 Triple bonds consist of one s and two p. e.g., C2H2

  8. Experiments indicate that all of C2H4’s atoms lie in the same plane. This suggests that p bonds introduce rigidity (i.e., a reluctance to rotate) into molecules. -- p bonding does NOT occur with sp3 hybridization, only sp and sp2 -- p bonding is more prevalent with small molecules (e.g., C, N, O) (Big atoms don’t allow enough p-orb. overlap for p bonds to form.)

  9. [ ] .. – .. O .. .. O– N =O .. .. .. .. Delocalized p Bonding Localized p bonds are between… two atoms only. -- e.g., C2H2, C2H4, N2 Delocalized p bonds are “smeared out” and shared among… > two atoms. -- These are common for molecules with… resonance structures. The nitrate ion (NO3–) has delocalized electrons. -- The electrons involved in these bonds are delocalized electrons.

  10. H H a 2p orbital on each C that is oriented to plane of m’cule. C C C C H H C C H H Consider benzene, C6H6. -- Each carbon atom is ___ hybridized. sp2 -- This leaves... -- 6 e– shared equally by 6 C atoms

  11. O = .. .. H H O H3C–C–CH3 – – = H–C–C–C–H – – H H O .. .. .. .. .. O–S=O .. .. [ ] O .. .. 2– .. .. .. .. O– –O .. S .. .. .. .. Which of the following exhibit delocalized bonding? 24 e– “NOPE.” propanone SO2 18 e– “YEP.” sulfur dioxide (res.) SO42– 32 e– “NOPE.” sulfate ion

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