# The Problem

I'm using unicode-math and the font TeX Gyre Pagella Math. Also, I use siunitx to denote my quantities. Unfortunately, the option \micro of siunitx doesn't get expanded to µ, but is dropped.

(The same behaviour can be observed when using mathspec in XeLaTeX)

# Minimal working example

Compile with Xe/LuaLaTeX.

\documentclass{standalone}
\usepackage{unicode-math}
\setmathfont{TeX Gyre Pagella Math}
\usepackage[mode = math]{siunitx}
\begin{document}
\SI{10}{\micro\m}
\end{document}


## Expected output

• You could do \def\SIUnitSymbolMicro{\mu} … but that doesn’t look like the right font settings (unslanted)? Jun 12, 2013 at 20:38
• I generated the expected output using \mathrm{\mu m}, so this means, there is an upright \mu. Jun 12, 2013 at 20:39
• What I meant is that it does look like the unslanted version of the italic glyph. The output is the same as yours with my definition. Jun 12, 2013 at 20:41
• According to unimath-symbols this is the only upright \mu. Internally siunitx tries to associate \textmu to \SIUnitSymbolMicro. Jun 12, 2013 at 20:47
• I think the solution from another answer about the µ is the correct solution while using the non math version for the main text too: \sisetup{math-micro=\text{µ},text-micro=µ} (it uses the special micro sign of UTF and not a mu). Jun 12, 2013 at 20:48

As explained in an answer by nlogax to microtype + siunitx and \micro - mysterious warnings Unicode has—besides the Greek Small Letter Mu character µ—a special Micro Sign µ.

That is to be used here. For some reason this is not present in unicode-math.
I assume that you also use TeX Gyre Pagella as your text font so we can use it from there with \text.

## Code

\documentclass{standalone}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Pagella}
\setmathfont{TeX Gyre Pagella Math}
\usepackage[mode = math]{siunitx}
\sisetup{math-micro=\text{µ},text-micro=µ}
\begin{document}
\SI{10}{\micro\m}
\SI[mode=text]{10}{\micro\m} % just for reference
\end{document}


## Output

• Just for more information: the character can also be input in the \sisetup line as ^^b5, if it's somehow difficult to use the Unicode character directly. Jun 12, 2013 at 21:24

This seems to work

\documentclass{standalone}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Pagella}
\setmathfont{TeX Gyre Pagella Math}
\usepackage[mode = math]{siunitx}
\def\SIUnitSymbolMicro{\textup{μ}}
\begin{document}

\SI{10}{\micro\m}
\end{document}


Note I needed to specify a text font as well.

• Why \def and not \cs_set:Npn \SIUnitSymbolMicro {\textup{μ}}? Jun 12, 2013 at 21:10