Chemical naming conventions

I’d probably not make a great scientist–too easily distracted. Trying to refresh my knowledge of highschool chemistry, I keep wanting to travel down rabbit holes. Instead of just remembering that chemical x is called whatever, I keep wanting to look up the history of the suffixes for names and the like. I’m assuming we should blame Latin or Greek. It’s usually Latin or Greek.

Because I can never seem to remember what suffix applies to what, let’s take some notes for referencing later.

Naming cations

When naming cations, it’s super simple–for any ions which form solely with a standard charge, just add ‘ion’ after the element name. If it is a polyvalent molecule, note the charge in parenthesis instead.

Naming anions

Anions get the element root name truncated, and the suffix ide added to the end.

Ionic compounds

Always use the cation before the anion (“hydrogen chloride”, rather than “chloride hydrogen”).

The suffix largely depends on the oxidization of the anion.

• If the anion is single or two-element, typically use ide as the suffix. Examples: ${\text{Cl}}^{-}$: chloride, $\text{Na}\text{Cl}$: sodium chloride, ${\text{O}}^{2-}$: oxide.
• To differentiate between ite and ate, you need to compare compounds which vary solely by the number of oxygen atoms in the molecule. Those which contain more get the suffix ate whereas those with fewer get ite. This is relative to similar compounds, so there isn’t a hard way to say “this much oxygen gets this ending.” An example, $\text{S}{\text{O}}_4^{2-}$ is sulfate, but $\text{S}{\text{O}}_3^{2-}$ is sulfite but $\text{N}{\text{O}}_3^{-}$ is nitrate and $\text{N}{\text{O}}_2^{-}$ is nitrite.

For polyvalent compounds, the preference is to use the charge notation; however, it is still possible to see common name. This leads to additional suffixes.

Using Iron $\text{Fe}$ as the example, iron(II) chloride is called ferrous (ous) chloride $\text{Fe}{\text{Cl}}_2$ whereas iron(III) chloride is called ferric (ic) chloride $\text{Fe}{\text{Cl}}_3$. This stays constant throughout.

Bases

Bases are (usually) named like ionic compounds: cation plus anion.

Acids

Acids are similar, but rather than being two separate words describing the cation and anion, it becomes a compound word. To further complicate things, the suffix changes depending on the anion.

• For anions which do not include any oxygen, they receive the prefix hydro. So $\text{H}\text{Cl}$ is hydrochloric acid because it is hydrogen + chloride.
• For anions which end in ide, the compound word now ends in ic. For example, $\text{H}\text{Cl}$ is hydrochloric acid (hydrogen + chloride).
• For anions which end in ate, the compound also ends in ic. For example, ${\text{H}}_2\text{S}{\text{O}}_4$ is sulfuric acid (hydrogen + sulphate).
• For anions which end in ite, the compound ends in ous. For example, ${\text{H}}_3\text{P}{\text{O}}_3$ is phosphorous acid (hydrogen + phosphite).