When naming ionic compounds, when is '-ate' used instead of '-ide'?
When an element becomes an anion (- charged), it takes on the name "-ide".
The ending of "-ate" is usually used with certain polyatomic ions. For example,
"-ate" is also used when the central atom of a polyatomic ion has a higher oxidation number (usually means more oxygen atoms around it).
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
Hope that helps.