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Solutions for Structure and Properties of Organic Molecules
N C
O
N
H
H N C
O
N
H
H
sp2
29 The second and third resonance forms of urea are minor but still significant. They show that the 
nitrogen-carbon bonds have some double bond character, requiring that the nitrogens be sp2 hybridized 
with bond angles approaching 120°.
C H
H
C
O
CC H
H
C
O
CH
H
H
H
H
Hsp3
(a) The major resonance contributor shows a carbon-carbon double bond, suggesting that both carbons are 
sp2 hybridized with trigonal planar geometry. The CH3 carbon is sp3 hybridized with tetrahedral geometry.
sp2
majorminor
30
N C
H
C C
H
HH
H H
N C
H
C C
H
HH
H H
N C
H
C C
H
HH
H H
(b) The major resonance contributor shows a carbon-nitrogen double bond, suggesting that all three 
carbons and the nitrogen are sp2 hybridized with trigonal planar geometry.
majorminor minor
(c) The nitrogen and the carbon bonded to it are sp hybridized; the other carbon is sp2. This ion has 
linear geometry. See the solution to 7(e) in this manual for an orbital picture.
C C
H
H
N C C
H
H
N
minor major
31 In (c), (d), and (e), the unshadowed p orbitals are vertical and parallel. The shadowed p orbitals are 
perpendicular and horizontal.
C
H3C
H3C
O
C N
H(a) (b)
H C C
C
N
CC
H H
H H
CH3 C C C
O
H
(c)
(d) (e)
C C C
H3C
H
CH3
H
H
H H
H
NC
O
N
H
H H
H
sp2
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