Ch 9 – Covalent Bonding: Orbitals

VSEPR Model VSEPR – valence shell electron pair repulsion model Is useful in predicting the geometries of covalently bonded molecules The structure around a given atom is determined principally by minimizing electron-pair repulsions

Hybridization Some atoms combine orbitals so they can move electrons around and have more electrons available for bonding. This is called hybridization.

sp3 Hybridization The s orbital and the three p orbitals combine to create 4 equal energy orbitals. Each hybrid orbital is ¼ s and ¾ p character.

With all orbitals being equidistant at 109 With all orbitals being equidistant at 109.5o, the result is a tetrahedral shape.

sp2 Hybridization The s orbital and two p orbitals combine to create 3 equal energy orbitals. Each hybrid orbital is 1/3 s and 2/3 p character.

The result are 3 hybrid orbitals and 1 unchanged orbital.

The resulting shape is trigonal planar with 120o bond angles.

sp Hybridization The s orbital and one p orbital combine to create 2 equal energy orbitals. Each hybrid orbital is ½ s and ½ p character. There are two unchanged p orbitals.

The resulting shape is linear with 180o bond angles.

dsp3 hybridization The key is having 5 pair of electrons around the central atom. They can be shared or unshared and the bond angles are 120o from side to side and 90o between top and bottom. 90o 120o

Trigonal bipyramidal 1 pair of d orbital electrons, 1 pair of s orbital electrons and 3 pair of p orbital electrons are hybridized.

d2sp3 hybridization The key is having 6 pair of electrons around the central atom. They can be shared or unshared and the bond angles are all 90o

Octahedral 2 pair of d orbital electrons, 1 pair of s orbital electrons and 3 pair of p orbital electrons are hybridized.