CHEM 281 Chapter 3: Chapter 3 Notes Part 8_ An Introduction to Organic Compounds
30 Aug 2018
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Chapter 3 Notes Part 8: An Introduction to Organic Compounds
● The name of any alkyl group bonded to nitrogen is preceded by an “N” (in italics) to
indicate that the group is bonded to a nitrogen rather than to a carbon.
● The substituents—regardless of whether they are attached to the nitrogen or to the
parent hydrocarbon—are listed in alphabetical order, and then a number or an “N” is
assigned to each one.
â—Ź The chain is numbered in the direction that gives the functional group suffix the
lowest number.
● Nitrogen compounds with four alkyl groups attached to the nitrogen—thereby giving the
nitrogen a positive formal charge—are called quaternary ammonium salts.
â—Ź Their names consist of the names of the alkyl groups in alphabetical order, followed
by “ammonium” (all one word) and then the name of the accompanying anion as a
separate word.
3.8: The Structures of Alkyl Halides, Alcohols, Ethers, and Amines
â—Ź The families of compounds you just learned how to name have structural resemblances
to the simpler compounds introduced in Chapter 1.
Alkyl Halides
● Let’s begin by looking at alkyl halides and their resemblance to alkanes.
â—Ź Both have the same geometry; the only difference is that a C-X bond of an alkyl halide
(where X denotes a halogen) has replaced a C-H bond of an alkane (Section 1.7).
â—Ź The C-X bond of an alkyl halide is formed from the overlap of an sp3 orbital of carbon
with an sp3 orbital of the halogen.
â—Ź Fluorine uses a 2sp3 orbital to overlap with a 2sp3 orbital of carbon, chlorine uses a
3sp3 orbital, bromine a 4sp3 orbital, and iodine a 5sp3 orbital.
â—Ź Thus, the C-X bond becomes longer and weaker as the size of the halogen increases
because the electron density of the orbital decreases with increasing volume.
Document Summary
Chapter 3 notes part 8: an introduction to organic compounds. The name of any alkyl group bonded to nitrogen is preceded by an n (in italics) to indicate that the group is bonded to a nitrogen rather than to a carbon. The substituents regardless of whether they are attached to the nitrogen or to the parent hydrocarbon are listed in alphabetical order, and then a number or an n is assigned to each one. The chain is numbered in the direction that gives the functional group suffix the lowest number. Nitrogen compounds with four alkyl groups attached to the nitrogen thereby giving the nitrogen a positive formal charge are called quaternary ammonium salts. Their names consist of the names of the alkyl groups in alphabetical order, followed by ammonium (all one word) and then the name of the accompanying anion as a separate word. 3. 8: the structures of alkyl halides, alcohols, ethers, and amines.
