argonium
... that argonium, an ion composed of an argon atom and a proton, was the first noble gas molecular ion to be found in interstellar space?
... that <b id="mweg"><a href="./Argonium" id="mwew" rel="mw:WikiLink" title="Argonium">argonium</a></b>, an ion composed of an argon atom and a proton, was the first <a href="./Noble_gas" id="mwfA" rel="mw:WikiLink" title="Noble gas">noble gas</a> molecular ion to be found in interstellar space?