number with subscript in siunitx

Question

I would like to use output-decimal-marker = {--} in siunitx to align a column with molecular transitions where the states are separated by --. However I get a Missing $ inserted error when the state includes a subscript.

\documentclass{article}
\usepackage{siunitx}

\begin{document}

\begin{table}
  \begin{tabular}{ S[output-decimal-marker = {--}] }
    3_1.2_1
  \end{tabular}
\end{table}

\end{document}

How could this work for numbers with subscripts?

Answer 1

Do you want something like that?

\documentclass{article}
\usepackage{siunitx}

\begin{document}

\begin{table}
  \begin{tabular}{ S[output-decimal-marker = {--},parse-numbers=false] }
    3_1.2_1
  \end{tabular}
\end{table}

\end{document}