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IUPAC Nomenclature of Haloalkanes

Haloalkanes (also called alkyl halides) are organic compounds containing a halogen atom (F, Cl, Br, or I) attached to an aliphatic carbon chain. The IUPAC (International Union of Pure and Applied Chemistry) system provides standardized rules for naming these compounds.

✅ General Formula of Haloalkanes:

𝑅
−
𝑋
R−X
Where:

𝑅
R = Alkyl group (like methyl, ethyl, etc.)

𝑋
X = Halogen atom (F, Cl, Br, I)

🔹 Steps in IUPAC Naming of Haloalkanes:
1. Identify the longest continuous carbon chain

This becomes the parent hydrocarbon (alkane base name: methane, ethane, propane, etc.)

2. Number the carbon chain

Number the chain from the end nearest to the halogen atom to give it the lowest possible locant (position number).

3. Identify and name the halogen substituent

Use a prefix based on the halogen:

Fluoro (F)

Chloro (Cl)

Bromo (Br)

Iodo (I)

4. Name and number other substituents (if present)

If there are alkyl groups (like methyl, ethyl), include and number them too.

List substituents in alphabetical order (ignoring prefixes like di-, tri-, etc.)

5. Combine all parts of the name

Use locants, prefixes, and the base name to write the full IUPAC name.

🔸 Examples:
Example 1:

Structure: CH₃–CH₂–CH₂–Cl

Longest chain: 3 carbons → propane

Halogen: chlorine at C-1
👉 Name: 1-chloropropane

Example 2:

Structure: CH₃–CH(Cl)–CH₃

Longest chain: 3 carbons → propane

Halogen: chlorine at C-2
👉 Name: 2-chloropropane

Example 3:

Structure: CH₃–C(Br)(CH₃)–CH₂–CH₃

Longest chain: 4 carbons → butane

Substituents: Bromo and methyl at C-2
👉 Name: 2-bromo-2-methylbutane

✅ Types of Haloalkanes:

Primary (1°): Halogen attached to a carbon bonded to only one other carbon (e.g., CH₃CH₂Cl)

Secondary (2°): Carbon with halogen is bonded to two other carbons (e.g., CH₃CHClCH₃)

Tertiary (3°): Carbon with halogen is bonded to three other carbons (e.g., (CH₃)₃CCl)
IUPAC Nomenclature

Haloalkanes

Alkyl Halides

Organic Chemistry

Halogen Substituents

Functional Groups

Primary Secondary Tertiary Halides

Fluoro Chloro Bromo Iodo

Naming Rules

Substituent Priority

Longest Chain Rule

Numbering Carbon Chain

Organic Compound Naming

Structural Formula

Prefix and Locant