Orbital bonding, hybridization

sp3 hybrid orbitals

tetrahedral Ex CH4, most carbon molecule Moves one electron in a orbitals to pz orbital to produce 4 valence orbitals, each with one electron S character: 25% P character: 75%

Hybridization

the mixing of several atomic orbitals to form the same total number of equivalent hybrid orbitals Makes all the bonds to a central atom equivalent to each other

sp2 hybrid orbitals

trigonal planar (120 apart) When one S orbital is mixed with 2 P orbitals, sp2 hybridized orbitals are formed Seen in alkenes 3rd p orbital is left unhybridized -this is the orbital that participates in the pi bond of the double bond 2 of the sp2 hybrid orbitals participate in a single bond and the other lines up with the pi bond (ex ethene) S character: 33% P character: 66%s

Conjugation

Alternating single and multiple bonds Allows for resonance

double and triple bonds

Double: one sigma one pi Triple: one sigma 2 pi

Resonance

Occurs in molecules with conjugated bonds Pi bonds can delocalize and add stability Resonance forms are not in equilibrium. True form is a hybrid of the resonance structures Structure most favored has minimum formal charge magnitude -or form full octets around highly electronegative atoms

Hybridization trick

Sum of exponents = number of atoms bonded to central atom

Other hybridizations

Trigonal bipyramidal: sp3d (dsp3) -coordination number of 5 Octahedral: sp3d2 -coordination number 6

Molecular orbitaks

When 2 atomic orbitals combine Obtained by Adding or subtracting wave functions of atomic orbitals If signs of wave functions are the same, lower energy (more stable) bonding orbital formed If signs are different, higher energy(less stable) anti bonding orbital produces Molecular orbitals can be bonding or anti-bonding, depending on the signs of the atomic orbitals used to form them Head to head or tail to tail overlap of atomic orbitals results in a pi bond

pi bond

a bond that is formed when parallel orbitals overlap to share electrons. When two P orbitals lineup in parallel (side-by-side), electron clouds overlap and a pi bond is formed Hinder rotation

sigma bond

a single covalent bond that is formed when an electron pair is shared by the direct overlap of bonding orbitals Head to head or tail to tail overlap All single bonds are pi bonds holding 2 electrons Free rotation

sp hybrid orbitals

linear (180) Can form triple bond (or two double bonds in a row) - two of the p orbitals unhybridized to form pi bonds -ex ethyne, CO2 3rd p orbital combines with s to form sp hybrid S character: 50% P character: 50%

hybrid orbitals

orbitals of equal energy produced by the combination of 2 or more orbitals on the same atom We can merge 3 P orbitals and one S orbital to get 4 identical orbitals with new hybridized shapes