# siunitx: µ doesn't work

I'm using TeXnicCenter for Windows (7) and I'm a bloody beginner in everything that concerns LaTeX. I'm using the siunitx package for mathematical formulas and it works just fine... with one exception. The \micro (e.g. \si{\micro}) command doesn't work! It simply doesn't show the µ in the PDF file. I've tried to use \u as well without success. Does anybody know what the error could be?

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\micro is not a unit (it is a quantifier), it is hardly ever written on its own. Have you tried \si{\micro\metre}? –  daleif Nov 7 '11 at 14:52
Welcome to TeX.sx! Please add a minimal working example (MWE) that illustrates your problem. –  N.N. Nov 7 '11 at 14:52
@daleif Sounds like an answer to me ... –  Joseph Wright Nov 7 '11 at 16:51
@Chris: As daleif has already said, \micro is a prefix and will print 'µ', while something like \micro\metre is a prefixed unit and will print 'µm'. Your comments on Marco's answer indicate that there is something else up, but without a minimal example it's not really possible to give any more advice. –  Joseph Wright Nov 8 '11 at 8:46
PS: Maybe you want to switch from TXC to TexMaker‌​, because TXC 1 does not support UTF-8 (TXC 2 will) but TexMaker does. Plus TexMaker is available for Win, Linux and Mac. –  matth Nov 10 '11 at 15:53

I’ll throw this in here, as my search for a solution led me here, but my problem was another one.

Using XeTeX and Latin Modern, I found that the greek letter μ does not work. However, the Unicode micro sign μ does work.

Knowing that, I added \sisetup{math-micro=\text{µ},text-micro=µ}, and now all seems well.

To clarify, use

µ
MICRO SIGN
Unicode: U+00B5, UTF-8: C2 B5


and not

μ
GREEK SMALL LETTER MU
Unicode: U+03BC, UTF-8: CE BC


for great justice.

MWE for my setup (XeTeX on OS X):

\documentclass{standalone}
\usepackage{fontspec}
\usepackage{siunitx}
% Note that the sign must be
%  µ
%  MICRO SIGN
%  Unicode: U+00B5, UTF-8: C2 B5
% and \emph{not}
%  μ
%  GREEK SMALL LETTER MU
%  Unicode: U+03BC, UTF-8: CE BC
\sisetup{math-micro=\text{µ},text-micro=µ}

\begin{document}
Now you can \si\micro\ all the things.
\end{document}


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Nice one! It would be great if you can provide a 10-20 lines of compilable LaTeX file with this working in action. We usually even put a screenshot of the resulting file to show the effect in action. –  percusse May 8 '12 at 10:46
That is what I recommend in the manual :-) –  Joseph Wright May 8 '12 at 10:55
@JosephWright When I copy the line from the manual, I get the greek letter. In fact, when I copy the one from my own document which is set up to use the micro sign, I also get the greek letter! Not sure why, but might be worth pointing out. :) –  nlogax May 8 '12 at 11:26
@nlogax The document has to work with pdfLaTeX, so I can only use what is available there. I'm expecting people using XeLaTeX/LuaLaTeX to use their system character map application to sort this out. –  Joseph Wright May 8 '12 at 11:50
Thank you for your nice example! –  percusse May 8 '12 at 11:59

Here is a MWE which compiles fine, using the command @daleif suggested

\documentclass[a4paper,final]{article}

\usepackage[T1]{fontenc}
\usepackage[]{lmodern}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}

\usepackage[]{siunitx}
\usepackage{textcomp}

\begin{document}

Greek letter \textmu{} in normal text.
Greek letter µ in normal text.
The unit for viscosity is \si{\micro\pascal}.
Just the \si{\micro} is not a SI unit but it works anyway.
Some number with unit \SI{51}{\micro\metre} lorem ipsum.
A number with unit in a formula $\SI{123}{\micro\metre}$ dolor sit amet.

\end{document}


As shown in the example, use \si for just units and capital \SI for a value-with-unit-combination.
And if you want a plain µ in the text, you could also try the command \textmu which is made available by the package \usepackage{textcomp}

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\si is for formatting units, \SI is for formatting a number-plus-unit combination (a 'quantity'). –  Joseph Wright Nov 8 '11 at 10:13
Thanks, I edited the text –  matth Dec 1 '11 at 17:02

Depending on which engine and encoding you use, you can just write a literal μ. Or you can typeset it in math mode as a variable $\mu$. It depends on what use the μ has in your document.

If it is a quantifier then add the corresponding unit as daleif already pointed out in the comment.

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Thank you all, so the $\mu$ and the plain µ are both working. The \si{\micro\metre} doesn't :( The problem is that the two working methods return a µ. Is there a possibility to get a normal µ still? –  Chris Nov 7 '11 at 20:37
If a plain µ yields a slanted µ, then it seems that your font simply doesn't have an upright µ. What is the result of $\mathup\mu$? –  Marco Nov 7 '11 at 20:57
Again it returns only a µ. Is there no way to add an upright µ to my font? –  Chris Nov 7 '11 at 21:58
You don't really want to add a glyph to your font. But nothing prevents you from defining a command that inserts an upright µ from another font. –  Marco Nov 7 '11 at 22:02
Or you can use \DeclareUnicodeCharacter to automate this. Or see this or this –  Marco Nov 7 '11 at 22:08