io vs íon, What's the Difference?

Which to use

“io” is an adverb and “íon” is a noun - they look or sound alike but fill different roles in a sentence.

#18,900
“io” frequency rank: #44,174
“íon” frequency rank: 63074
confusion score

Side-by-Side Comparison

Feature	io	íon
Definition	sempre	espécie química eletricamente carregada, geralmente um átomo ou molécula que perdeu ou ganhou elétrons

Letter map: io vs íon

Shared letters muted; letters that set io and íon apart highlighted. Shared run: 1.

2 ch

3 ch

íon

Role in the sentence - io and íon

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: io is anadverb and íonanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 63074, derived from the frequency rank of both members and their visual similarity.

io is recorded at frequency rank #18,900, classified as anadv, pronounced /ˈi.o/, /ˈi.ɔ/. íon is at rank #44,174, tagged as anoun.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 63074, this pair ranks #6,370 of 75,631 scored Portuguese confusable pairs - among the most confusable pairs.

Orthographic DNA of io vs íon

Shared letters: o. Private to "io": i. Private to "íon": ní.

"io" · 2 letters · shape VV · "íon" · 3 letters · shape VVC

Frequently Asked Questions

Can "io" and "íon" be used interchangeably?

No - they are not even the same part of speech. "io" is an adverb and "íon" a noun, so a sentence built for one is usually ungrammatical with the other.

In ordinary Portuguese text, does "io" or "íon" show up more?

"io" is the more common of the two: it sits at frequency rank #18,900 in our Portuguese list, against #44,174 for "íon". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Done with this confusable. These links stay specific to "io" and "íon".

Full dictionary entry for "io" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "íon" - compare definitions side by side with the headword page. Word entry
This pair ranks #6,370 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"io" and "íon" also get mixed up with nearby pairs, the highest-scored neighbour is "ino vs íon". Nearby pair

Confusion rank #6,370 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.