I need the *per mille* (`\textperthousand`

) symbol in math mode and text in a `classicthesis`

style document. Instead, in the PDF, I get a percent symbol followed by a small, black square.

For example, this LaTeX code

```
For example, for carbon-13,
\[
\delta^{13}{\textrm C} =
\left(
\frac{ \left( \frac{^{13}\textrm C}{^{12}\textrm C} \right) _{sample}- \left(\frac{^{13}\textrm C}{^{12}\textrm C}\right)_{standard}}%
{\left(\frac{^{13}\textrm C}{^{12}\textrm C}\right)_{standard}}%
\right) \times 1000 \qquad\textperthousand
\]
This value, represented by a delta ($\delta$) prefixing the mass number and symbol for the element, is in parts per thousand or \emph{permil} (\textperthousand).
```

produces correct output when typeset using PDFLaTeX or XeLaTeX using the `article`

style

but not when typeset using PDFLaTeX with the `classicthesis`

style.

Is there something I can do to obtain the correct symbol?

## Best Answer

The

`\textperthousand`

command is available both with the T1 encoding (used by`classicthesis`

) and the TS1 encoding.However, the Palatino font loaded via the

`mathpazo`

package by`classicthesis`

hasn't the required glyph: in the T1 encoding`\textperthousand`

is built by adding a small zero next to`%`

and the small zero is missing (a black square is used to show this).However the Palatino text companion font has the glyph

`\textperthousand`

, so all you need to do is to load`textcomp`

: addto your document preamble.

Note that

`\textperthousand`

is not legal in math mode and produces a warning. You can avoid it by usingor, better, by loading also

`amsmath`

and usingYou may want to define a variant command that works both in text and math mode: