sp2 Hybrid Orbitals sp2hybrid orbitals unhybridized P:orbital ·3 VSEPR pairs sp Trigonal planar geometry 。120°bond angle sp2hybrid carbon atom (viewed from the side) Chapter 2 16
Chapter 2 16 sp2 Hybrid Orbitals • 3 VSEPR pairs • Trigonal planar geometry • 120° bond angle
Solved Problem 2 Borane(BH3)is not stable under normal conditions,but it has been detected at low pressure. (a)Draw the Lewis structure for borane.(b)Draw a diagram of the bonding in this molecule,and label the hybridization of each orbital.(c)Predict the H-B-H bond angle. Solution There are only six valence electrons in borane.Boron has a single bond to each of the three hydrogen atoms. The best bonding orbitals are those that provide B the greatest electron density in the bonding HH region while keeping the three pairs of bonding electrons as far apart as possible.Hybridization of an s orbital with two p orbitals gives three sp2 hybrid orbitals directed 120 apart.Overlap of 120° 120 these orbitals with the hydrogen Is orbitals gives B a planar,trigonal molecule.(Note that the small back lobes of the hybrid orbitals have been sp omitted.) 120 Chapter 2 1>
Chapter 2 17 Borane (BH3 ) is not stable under normal conditions, but it has been detected at low pressure. (a) Draw the Lewis structure for borane. (b) Draw a diagram of the bonding in this molecule, and label the hybridization of each orbital. (c) Predict the H–B–H bond angle. There are only six valence electrons in borane. Boron has a single bond to each of the three hydrogen atoms. The best bonding orbitals are those that provide the greatest electron density in the bonding region while keeping the three pairs of bonding electrons as far apart as possible. Hybridization of an s orbital with two p orbitals gives three sp2 hybrid orbitals directed 120° apart. Overlap of these orbitals with the hydrogen 1s orbitals gives a planar, trigonal molecule. (Note that the small back lobes of the hybrid orbitals have been omitted.) Solved Problem 2 Solution