un-ionized

Etymology
From, from.

Adjective

 * 1)  Not ionized.

Usage notes
At least one manual of style, and various publications' style sheets inspired by it, specifies the hyphenated style un-ionized among the alternative forms of this word, simply to avoid the homography with unionized as in "having a union", whereas there is no compelling reason not to avoid it. It is thus a rare exception to their general rule of preferring the solid form for affixed words by default, with exceptions only for clarity. Other words in this class are versus,  versus , and  versus. The exception does not apply to any other forms of these words for which no ambiguity exists: thus, and.