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132 Chapter 3
Copyright © 2017 Pearson Education, Inc.
cycloalkane
an alkane with its carbon chain arranged in a closed ring.
1,3-diaxial interaction
the interaction between an axial substituent and one of the other two axial substitu-
ents on the same side of a cyclohexane ring.
dipole–dipole interaction
an interaction between the dipole of one molecule and the dipole of another.
eclipsed conformer
a conformer in which the bonds on adjacent carbons are parallel to each other
when viewed looking down the carbon–carbon bond.
equatorial bond
a bond of the chair conformer of cyclohexane that juts out from the ring but does
not point directly up or directly down.
ether
a compound in which an oxygen is bonded to two alkyl substituents (ROR).
flagpole hydrogens
the two hydrogens in the boat conformer of cyclohexane that are at the 1- and
4-positions of the ring.
functional group
the center of reactivity of a molecule.
gauche conformer
a staggered conformer in which the largest substituents bonded to the two
carbons are gauche to each other; that is, their bonds have a dihedral angle of
approximately
60
°
.
Y
X
60º
The substituents are gauche to each other.
gauche interaction
the interaction between two atoms or groups that are gauche to each other.
geometric isomers
cis–trans isomers.
half-chair conformer
the least stable conformer of cyclohexane.
homologue
a member of a homologous series.
homologous series
a family of compounds in which each member differs from the next by one methy-
lene group.
hydrocarbon
a compound that contains only carbon and hydrogen.
hydrogen bond
an unusually strong dipole–dipole interaction between a hydrogen bonded to O, N,
or F and the lone pair of a different O, N, or F.
hyperconjugation
delocalization of electrons by the overlap of a
s
orbital with an empty orbital.
induced-dipole–induced-
an interaction between a temporary dipole in one molecule and the dipole
dipole interaction
that the temporary dipole induces in another molecule.