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

1 Answer
Dave
Apr 1, 2018

See Below

Explanation:

When an element becomes an anion (- charged), it takes on the name "-ide". #Cl_2# becomes two #Cl^-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, #CH_3COO^-# 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:
#ClO^-1# - hypochorite ion
#ClO_2^-1# - chlorite ion
#ClO_3^-1# - chlorate ion
#ClO_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 #COO^-#

Hope that helps.

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