Negatively charged particle (5)
I believe the answer is:
anion
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">negatively charged particle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for anion that I've seen before include "Negatively charged particle" , "One's charged" .)