How to add subfigures in achemso

Question

I'm writing supporting information using \documentclass{article} for a journal and I am asked to use the achemso package instead. but when I change \documentclass{article} to \documentclass[journal=jacsat,manuscript=article]{achemso}, I cannot use subfigures package and the whole layout is affected. Is there any way to use subfigures using achemso package?

Answer 1

You can use subcaption package instead:

\documentclass[journal=jacsat,manuscript=suppinfo]{achemso}
\usepackage{duckuments}
\usepackage{lipsum}
\usepackage{subcaption}
\usepackage{graphicx}
\author{First Author}
\email{firstauthor@unknown.uu}
\author{Second Author}
\email{secondauthor@unknown.uu}
\affiliation[First University]
{Department of Chemistry, First University, Unknown Town}
\alsoaffiliation[Second University]
{Department of Chemistry, Second University, Nearby Town}
\title{Paper title}
\begin{document}
\lipsum[1-2]
\begin{figure}[ht]
    \begin{subfigure}{0.3\linewidth}
        \includegraphics[width=\textwidth]{example-image-duck}
        \caption{Subcaption A}
    \end{subfigure}
\hfill
    \begin{subfigure}{0.3\linewidth}
    \includegraphics[width=\textwidth]{example-image-duck}
    \caption{Subcaption B}
\end{subfigure}
\hfill
    \begin{subfigure}{0.3\linewidth}
    \includegraphics[width=\textwidth]{example-image-duck}
    \caption{Subcaption C}
\end{subfigure}
    \caption{Caption}
\end{figure}
\lipsum[3-4]
\end{document}

Answer 2

The subfigure package has been obsolete for a couple of decades.

The successor package subfig can be used with achemso with no problem.

\documentclass[
  journal=jacsat,
  manuscript=article
]{achemso}
\usepackage{chemformula} % Formula subscripts using \ch{}
\usepackage[T1]{fontenc} % Use modern font encodings
\usepackage{graphicx}
\usepackage{subfig}
\author{Andrew N. Other}
\altaffiliation{A shared footnote}
\author{Fred T. Secondauthor}
\altaffiliation{Current address: Some other place, Othert"own,
Germany}
\author{I. Ken Groupleader}
\altaffiliation{A shared footnote}
\email{i.k.groupleader@unknown.uu}
\phone{+123 (0)123 4445556}
\fax{+123 (0)123 4445557}
\affiliation[Unknown University]
{Department of Chemistry, Unknown University, Unknown Town}
\alsoaffiliation[Second University]
{Department of Chemistry, Second University, Nearby Town}
\author{Susanne K. Laborator}
\email{s.k.laborator@bigpharma.co}
\affiliation[BigPharma]
{Lead Discovery, BigPharma, Big Town, USA}
\author{Kay T. Finally}
\affiliation[Unknown University]
{Department of Chemistry, Unknown University, Unknown Town}
\alsoaffiliation[Second University]
{Department of Chemistry, Second University, Nearby Town}
\title[An \textsf{achemso} demo]
  {A demonstration of the \textsf{achemso} \LaTeX

   class\footnote{A footnote for the title}}
\abbreviations{IR,NMR,UV}
\keywords{American Chemical Society, \LaTeX}
\begin{document}
\begin{abstract}
  This is an example document for the \textsf{achemso} document
  class, intended for submissions to the American Chemical Society
  for publication. The class is based on the standard \LaTeXe

  \textsf{report} file, and does not seek to reproduce the appearance
  of a published paper.
This is an abstract for the \textsf{achemso} document class
  demonstration document.  An abstract is only allowed for certain
  manuscript types.  The selection of \texttt{journal} and
  \texttt{manuscript} will determine if an abstract is valid.  If
  not, the class will issue an appropriate error.
\end{abstract}
\section{Introduction}
This is a paragraph of text to fill the introduction of the
demonstration file.  The demonstration file attempts to show the
modifications of the standard \LaTeX\ macros that are implemented by
the \textsf{achemso} class.  These are mainly concerned with content,
as opposed to appearance.
\begin{figure}[htp]
\centering
\subfloat[Subcaption]{\includegraphics[width=0.4\columnwidth]{example-image}}\hfill
\subfloat[Subcaption]{\includegraphics[width=0.4\columnwidth]{example-image}}
\caption{Caption}
\end{figure}
\end{document}

You can also use subcaption instead.