# Should Greek letters inserted in text (using math mode, mostly) always be italic?

The least painful way I know of inserting a Greek letter in a text is to use the math mode and the corresponding command. This will produce an alpha letter :

$\alpha$


But this always produces an italic letter. I never thought about it until now, but when should this letter be italic, and when should it not?

Furthermore, if I am talking about microseconds in my text, there will be one Latin and one Greek letter side by side. Which of the following should I use?

1- The average time of this event is 50 $\mu s$.
2- The average time of this event is 50 $\mu$s.
3- The average time of this event is 50 $\mathrm{\mu s}. 4- The average time of this event is 50 μs.  Now to me it's either #1 or #3, as #2 produces one italic letter and one normal letter (that's kind of a visual clash), and #4 is only usable if your document is encoded using UTF-X. What do you do when facing this? - You seem to be asking two separate questions here. One is about Greek letters in general (which could be, for example, for including a Greek word in otherwise Latin-script text). The second is about the micro symbol, which has been asked before (tex.stackexchange.com/questions/522) and is a separate issue. – Joseph Wright Jan 15 '11 at 22:11 ## 2 Answers For the case of units, you should use the siunitx package. \documentclass{article} \usepackage{siunitx} \begin{document} The average time of this event is \SI{50}{\micro\second}. \end{document}  I guess I should mention the upgreek package. The average time of this event is 50~$\upmu\$s.


but this doesn't look as good.

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Just a note: While the upgreek package obviously is the wrong choice for the micro symbol it is very handy for the naming of chemical compounds which frequently contain upright greek letters. For these one could also use the textgreek package. –  cgnieder Aug 22 '12 at 22:09

My dissertation involves a lot of chemistry in the micromolar concentration range. A small "mu" is the only greek letter I usually need to write the units I usually use. I found that the most efficient way to make it look write is to use the package textcomp and call the letter by writing \textmu. This also keeps the "mu" formatted in the same font as the rest of the document.

\documentclass{article}
\usepackage{textcomp}
\begin{document}
The initial concentration was 50 {\textmu}M.
\end{document}


Which gives this result:

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That does not give the right spacing between number and unit. Try using the units or SIunits package instead. –  queueoverflow Oct 27 '12 at 14:05