# When naming ionic compounds, when is '-ate' used instead of '-ide'?

Apr 1, 2018

See Below

#### Explanation:

When an element becomes an anion (- charged), it takes on the name "-ide". $C {l}_{2}$ becomes two $C {l}^{-} 1$ ions, those ions are called "Chloride ions". Same for Oxide ions, Bromide ions.

The ending of "-ate" is usually used with certain polyatomic ions. For example, $C {H}_{3} C O {O}^{-}$ is acetate ion.

"-ate" is also used when the central atom of a polyatomic ion has a higher oxidation number (usually means more oxygen atoms around it).

For example:
$C l {O}^{-} 1$ - hypochorite ion
$C l {O}_{2}^{-} 1$ - chlorite ion
$C l {O}_{3}^{-} 1$ - chlorate ion
$C l {O}_{4}^{-} 1$ - perchlorate ion

So if there are polyatomic ions that are related and they have different numbers of oxygens, the one with the less number will usually get the ending -ite....and the one with more oxygens will usually get the ending -ate.

In biochemistry, the name -ate usually means the conjugate base of a weak acid. Pyruvate, stearic acid vs. stearate, acetate...these all basically have COOH turning to $C O {O}^{-}$

Hope that helps.