Chemistry · Ch 6 — Haloalkanes and Haloarenes
On the Basis of Number of Halogen Atoms
On the Basis of Number of Halogen Atoms
Halogen derivatives can first be sorted purely by counting how many halogen atoms their structure contains.
Monohalogen Compounds
A single halogen atom is present. A monohaloalkane built on a two-carbon chain is written as
and a monosubstituted benzene ring gives a monohaloarene, with the single X attached directly to the ring.
Dihalogen Compounds
Two halogen atoms are present. A dihaloalkane based on ethane carries one X on each carbon:
The aromatic counterpart, a dihaloarene, has two X atoms substituted on the benzene ring.
Trihalogen (and Higher Polyhalogen) Compounds
Three or more halogen atoms are present — trihalo-, tetrahalo-, and so on are grouped together as polyhalogen compounds. A trihaloalkane built on a three-carbon chain, for instance, may be represented as
with the aromatic version, a trihaloarene, carrying three X atoms on the ring.
Drawn by us to help you understand the concept clearly, and verified to make sure it's accurate. For exams, practice from your textbook's own diagram.
The same mono/di/trihalogen split applies to the aromatic (haloarene) side of the family: a monosubstituted ring gives a monohaloarene, a ring bearing two halogens is a dihaloarene, and one bearing three is a trihaloarene -- the aromatic …
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