Chem101 14.1 - Hybridization and the LE Model

dsp³ hybridization

-five effective pairs requiring trigonal bipyramidal arrangement -5 dsp3 orbitals formed by linearly combining 1 d, 1 s, and 3 p orbitals -Overlap of dsp3 orbitals: http://butane.chem.uiuc.edu/cyerkes/Chem102AEFa07/Lecture_Notes_102/Lecture%2015%27-102_files/image087.jpg

d²sp³ hybridization

-six electron pairs requiring octahedral arrangement -6 d2sp3 orbitals that are linear combinations of 2 d, 1 s, and 3 p orbitals -Overlap of d2sp3 orbitals: http://butane.chem.uiuc.edu/cyerkes/Chem102AEFa07/Lecture_Notes_102/Lecture%2015%27-102_files/image042.jpg

sp hybridization

-two effective pairs around an atom -linear combinations of one s orbital and one p orbital -two 2p orbitals remain unchanged; π bonds -E level diagram: http://www.mhhe.com/physsci/chemistry/carey/student/olc/graphics/carey04oc/ch01/figures/ch15depthc.gif -Formation of sp orbitals: http://files.myopera.com/ennahoja/albums/232319/The%20formation%20of%20sp%20orbitals.jpg

sp³ hybridization

-used when a set of equivalent tetrahedral atomic orbitals is needed -linear combinations of 2s and 2p orbitals give 4 sp³ hybrid orbitals -4 sp³ hybrid orbitals combine to give tetrahedral geometry -E level diagram: http://science.uvu.edu/ochem/wp-content/images/H/hybridization8.png -Formation of sp3 orbitals: http://files.myopera.com/ennahoja/albums/232319/The%20formation%20of%20sp3%20hybrid%20orbitals.jpg

sp² hybridization

-used when an atom is surrounded by three effective pairs and needs trigonal planar arrangement -linear combinations of one 2s and two 2p orbitals -plane of sp2 hybrid orbitals is determined by which p orbitals used; px and py, then x-y plane -remaining 2p orbital is perpendicular to plane of sp2 orbitals -E level diagram: http://www.expertsmind.com/CMSImages/954_Hybridization%20-%20sp2.png -Formation of sp2 orbitals: http://www.chemtube3d.com/images/sp2hybrids_n.png

Steps to Describing Hybridization and Bonding within a Model Using the LE Model

1. Draw the Lewis strx. 2. determine the arrangement of electron pairs using the VSEPR model - how many electron pairs around each atom? 3. specify hybrid orbitals needed to accomodate

Aim of Localized Electron Model

Restructure atomic orbitals to account for bonding. *Create bonds of equal E and length *Create bonds of equal angle separation *Localize/directionalize electrons

sigma (σ) bond

covalent bond where electron pair is within overlap of hybrid orbitals

peripheral atoms are also assumed to hybridize to minimize...

electron-electron repulsions

electrons always _____ unhybridized orbitals electrons always _____ hybridized orbitals

electrons always between unhybridized orbitals electrons always in hybrid orbitals

Relationship among # of effective pairs and their spatial arrangement

http://wps.prenhall.com/wps/media/objects/165/169060/tool0904.gif

lone pairs occupy...

hybrid atomic orbitals

hybridization

mixing of the native atomic orbitals to form special orbitals for bonding

pi (π) bond

parallel p orbitals can share an electron pair; the electron pair is between the parallel p orbitals

multiple bonds contain...

sigma bonds and pi bonds