[Tex/LaTex] \ref not working with achemso

Question

I'm trying to write a document with the achemso package, but my \ref are not working right. achemso links to a package called cleveref, then renames cleveref's \cref into \ref, so any answers for cleveref should work here.

Example one:

\documentclass[journal=jacsat,layout=traditional]{achemso}
\usepackage{achemso} %loaded last due to clerverRef

\author{Canageek}
\title{Title}
\email{fake@email.ca}
\affiliation[University]{University, Canada}

\begin{document}
\section{Introduction \label{intro}}
blah blah blah blah

\section{two}
Will this work? See~\ref{intro}.

\end{document}

Produces as it's body text:

Introduction

blah blah blah blah

two

Will this work? See Footnote ∗.

Next example, since there is mention of a error with references in section titles in the cleveref manual.

\documentclass[journal=jacsat,layout=traditional]{achemso}
\usepackage{achemso} %loaded last due to clerverRef

\author{Canageek}
\title{Title}
\email{fake@email.ca}
\affiliation[University]{University, Canada}

\begin{document}
\section{Introduction}
 \label{intro}
blah blah blah blah

\section{two}
Will this work? See~\ref{intro}.

\end{document}

This gives the same output as above.
Oddly enough neither produce anything odd that I can find in the .log file.

\documentclass[journal=jacsat,layout=traditional,hyperref]{achemso}
\usepackage{hyperref}
\usepackage{achemso} %loaded last due to clerverRef


\author{Canageek}
\title{Title}
\email{fake@email.ca}
\affiliation[University]{University, Canada}

\begin{document}
\section{Introduction}
 \label{intro}
blah blah blah blah

\section{two}
Will this work? See~\ref{intro}.

\end{document}

Gives a different output: It replaces the * with a ??.
The .log file for this one also has the message

LaTeX Warning: cref reference format for label type `' undefined on input line
17.

Can anyone tell me what I'm doing wrong? I made sure to update my TeX Live install this morning when I had another problem, so everything should be up to date. Oh, and yes, I've made sure to delete everything but the test.tex file from the folder between compiles.

Answer 1

If you want to cross-reference the sections, they should have a number associated (to be used in cross-referencing) otherwise, the wrong string will be picked up to produce the cross-reference number (in your case, it will be the one created by \affiliation which explains why you were getting "Footnote").

achemso uses section numbers only where the journal uses these in print. You can use the \SectionNumbersOn command to force section numbering; however, if you use section numbers in a submission to a journal which does not use them, things may go a bit wrong later.

Your document could be something like this:

\documentclass[journal=jacsat,layout=traditional]{achemso}
\usepackage{achemso}

\SectionNumbersOn

\author{Canageek}
\title{Title}
\email{fake@email.ca}
\affiliation[University]{University, Canada}

\begin{document}
\section{Introduction}\label{intro}
blah blah blah blah

\section{two}
Will this work? See~\ref{intro}.

\end{document}