Biblatex – How to Italicize ‘et al.’ with \textcite or \citeauthor

Question

I'm using biblatex with the chem-rsc package option. I sometimes make use of the \textcite{<key>} or \citeauthor{<key>} commands to put the authors' name into text. When there are many, it writes "Bloke et al.", but I would like to make it put the "et al." in italics.

I'm sure there are some hacky ways of doing this by rewriting parts of commands. I'm hoping that there is some fairly straight forward and robust method for it though.

Answer 1

"et al." corresponds to the localization key andothers. In most styles it is set by the generic bibliography macro name:andothers. You can redefine this macro to wrap \bibstring{andothers} in \emph.

\documentclass{article}
\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=chem-rsc]{biblatex}

\renewbibmacro*{name:andothers}{% Based on name:andothers from biblatex.def
  \ifboolexpr{
    test {\ifnumequal{\value{listcount}}{\value{liststop}}}
    and
    test \ifmorenames
  }
    {\ifnumgreater{\value{liststop}}{1}
       {\finalandcomma}
       {}%
     \andothersdelim\bibstring[\emph]{andothers}}
    {}}

\addbibresource{biblatex-examples.bib}

\begin{document}
\textcite{companion} \citeauthor{companion}
\printbibliography
\end{document}