How do you name "CH"_3"Br"?

Nov 14, 2016

Well, you need to know what the name of the alkyl chains are, and the stem for the substituent.

• Alkyl groups are chains of $\text{CH}$ bonds, such as "H"_3"C"-("CH"_2)_n-.

The most common ones are:
$\text{Meth} -$: one carbon in the main chain
$\text{Eth} -$: two carbons in the main chain
$\text{Prop} -$: three carbons in the main chain
$\text{But} -$: four carbons in the main chain
$\text{Pent} -$: five carbons in the main chain
$\text{Hex} -$: six carbons in the main chain
$\text{Hept} -$: seven carbons in the main chain
$\text{Oct} -$: eight carbons in the main chain
$\text{Non} -$: nine carbons in the main chain
$\text{Dec} -$: ten carbons in the main chain

• Substituents are non-hydrogens, such as $- \text{Br}$, $- \text{Cl}$, $- \text{OH}$, $- {\text{NH}}_{2}$, etc. They each have their own stems, such as bromo, chloro, hydroxyl, or amino, in that order.

You have at least two ways you can name $\text{CH"_3"Br}$.

• Bromo + meth + ane, because a bromine substituent (bromo) is on a one-carbon alkyl chain (meth-), and the alkyl chain has no double or triple bonds (making it a haloalkane compound, specifically a bromoalkane compound, as compared to a bromoalkene or a bromoalkyne).
• Meth + yl brom + ide, because the one-carbon chain has the prefix "meth-", the "yl" is for hydrocarbon chains that are not terminated on the second end by a ${\text{CH}}_{3}$, and bromide is the name of the ${\text{Br}}^{-}$ anion.

So, two possible names are bromomethane or methyl bromide.