No way to insert ± in units

[MithicSpirit]

There appears to be no way to insert a ± symbol in units, since \pm is replaced with "pm" (for picometer). \mp for the opposite still works, however.

[josephwright]

That's true (or at least there is no convenient way), but then I've never come across a case where it was needed: can you point to one?

[MithicSpirit]

Yeah I've pretty much never had to do it either, except for an assignment where it was convenient to use the mass of a charged pion as a unit (\text{\ensuremath{m_{\pi^\pm}}}).