Do metals react with ammonia gas (not liquid phase)?
Wikipedia reports that magnesium nitride can be prepared:

By passing dry nitrogen over heated magnesium:
${\displaystyle{\begin{matrix}{}\\{\ce {{3Mg} + N2-&gt;[{\ce{800^{\circ }C}}]Mg3N2}}\\{}\end{matrix}}}$
or ammonia:
${\displaystyle{\begin{matrix}{}\\{\ce{{3Mg} + 2NH3-&gt;[{\ce{700^{\circ }C}}]{Mg3N2} + 3H2}}\\{}\end{matrix}}}$

No references are cited.