Good practices for creating tables

Question

Would you help me to make the table below look better? I don't need a beautiful table, just some frequent practices to make it looks better.

MWE

\begin{table}[H]
\centering
\begin{adjustbox}{width=0.8\textwidth}
\begin{threeparttable}
\caption{Estimación de pKa para ácidos, alcoholes y aminoácidos}\label{table:estimación_pka_RM1_con_aminoácidos}
\begin{tabular}{|l|c|c|c|c|c|}
\hline
 & \textbf{} & \multicolumn{4}{c|}{\textbf{RM1}} \\ \hline
 &  & \multicolumn{2}{c|}{\textbf{COSMO}} & \multicolumn{2}{c|}{\textbf{SS-COSMO}} \\ \hline
 & p$Ka_{\textrm{exp}}$(298K) & p$Ka_{\textrm{calc}}$ & $\Delta$p$Ka$ & p$Ka_{\textrm{calc}}$ & $\Delta$p$Ka$ \\ \hline
\textbf{Ácidos}&  &  &  &  &  \\ \hline
acético & 4.75 & 2.1 & 2.6 & 4.2 & 0.6 \\ \hline
láctico & 3.86 & 0.7 & 3.2 & 5.0 & -1.2 \\ \hline
benzoico & 4.2 & 1.1 & 3.1 & 1.6 & 2.6 \\ \hline
\textbf{MAE} &  &  & 3.1 &  & 1.6 \\ \hline
\end{tabular}
\begin{tablenotes}
\item[a]{Desprotonación de referencia}
\item[b] {\scriptsize Sin valor experimental}
\item {\scriptsize Estimación.}
\end{tablenotes}
\end{threeparttable}
\end{adjustbox}
\end{table}

Answer 1

My suggestion is using

• siunitx to align the numbers

• booktabs for nicer table rules and spacing:

and not:

• \begin{table}[H] this will disable most of the powerful floating mechanism of tex
• \begin{adjustbox}{width=0.8\textwidth} this will mess up the font size in the table

---

\documentclass[12pt,twoside
%,draft
]{report}

\usepackage[headheight=18pt,a4paper, width=150mm, top=25mm, bottom=25mm, bindingoffset=6mm, headsep=18pt]{geometry}
\usepackage[spanish,es-noquoting]{babel}
%interprete de idioma castellano
\usepackage[utf8]{inputenc} %relacionado al input
\usepackage[T1]{fontenc} 
\usepackage{booktabs}
\usepackage{siunitx}


\begin{document}


\begin{table}
  \centering
  \begin{tabular}{@{} l *{5}{S[table-format=-1.2]} @{}}
\toprule
&  & \multicolumn{4}{c}{RM1} \\ 
\cmidrule{3-6}
&  & \multicolumn{2}{c}{COSMO} & \multicolumn{2}{c}{SS-COSMO} \\ 
\cmidrule(r{5pt}){3-4}\cmidrule(l{5pt}){5-6}
& {p$Ka_{\text{exp}}$(\SI{298}{K})} & {p$Ka_{\text{calc}}$} & {$\Delta$p$Ka$} & {p$Ka_{\text{calc}}$} & {$\Delta$p$Ka$} \\
 \midrule 
Ácidos&  &  &  &  &  \\ 
cloroacético & 2.85 & 0.5 & 2.4 & 1.4 & 1.5 \\ 
4-clorobutírico & 4.52 & 5.0 & -0.5 & 4.7 & -0.2 \\ 
2-cloropentanoico &  & -2.3 &  & 1.0 & \\ 
2-clorobutírico & 2.86 & 0.6 & 2.2 & 0.4 & 2.5 \\ 
3-clorobutírico & 4.05 & 3.7 & 0.4 & 3.8 & 0.3 \\ 
acetoacético & 3.6 & 3.4 & 0.2 & 2.0 & 1.6 \\ 
bromoacético & 2.69 & 1.2 & 1.5 & 1.1 & 1.6 \\ 
dicloro-acético & 1.41 & -3.2 & 4.6 & -2.5 & 3.9 \\ 
iodoacético & 3.12 & 2.1 & 1.1 & 2.8 & 0.3 \\ 
L-valina & 2.29 & -1.9 & 4.2 & 2.6 & -0.3 \\ 
L-alanina & 2.34 & -1.6 & 3.9 & 2.3 & 0.0 \\ 
trichloroacético & 0.7 & -7.0 & 7.7 & -4.7 & 5.4 \\ 
2-chloropropanoico & 2.83 & 0.8 & 2.0 & 0.2 & 2.6 \\ 
3-chloropropanoico & 3.98 & 3.4 & 0.6 & 5.2 & -1.3 \\ 
3-hidroxipropanoico & 4.51 & 3.8 & 0.8 & 3.5 & 1.0 \\ 
acético & 4.75 & {ref} & {ref} & {ref} & {ref} \\ 
fluoroacético & 2.59 & 1.9 & 0.7 & -0.3 & 2.9 \\ 
fórmico & 3.75 & 6.4 & -2.6 & 4.3 & -0.6 \\ 
pirúvico & 2.39 & -0.3 & 2.7 & 1.3 & 1.1 \\ 
glioxílico & 3.18 & 0.3 & 2.9 & 1.0 & 2.2 \\ 
propanoico & 4.86 & 4.9 & -0.1 & 4.5 & 0.3 \\ 
butanoico & 4.83 & 5.2 & -0.3 & 4.7 & 0.1 \\ 
acrílico & 4.25 & 4.6 & -0.3 & 1.5 & 2.7 \\ 
láctico & 3.86 & 3.3 & 0.6 & 5.6 & -1.7 \\ 
benzoico & 4.2 & 3.7 & 0.5 & 2.2 & 2.0 \\ 
\midrule
MAE &  &  & 1.8 &  & 1.7\\
\bottomrule
\end{tabular}
\end{table}
\end{document}

Answer 2

Not so different from samcarter's answer, but with some valuable tricks.

The symbol “pKa” should not appear in italics, so I defined a couple of macros to deal with this and to simplify input.

The notes should not be in \scriptsize, which is way too small.

Avoid scaling tables and also special characters in \label.

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[spanish]{babel}

\usepackage{threeparttable}
\usepackage{siunitx} % for numeric tables
\usepackage{booktabs} % for better tables

\newcommand{\pKa}[1]{%
  \textnormal{pKa}%
  \if\relax\detokenize{#1}\relax
  \else
    \ensuremath{_{\mathrm{#1}}}%
  \fi
}
\newcommand{\DpKa}{\ensuremath{\Delta}\pKa{}}

\begin{document}

\begin{table}[htp]

\begin{threeparttable}

\caption{Estimación de \pKa{} para ácidos, alcoholes y aminoácidos}
\label{table:estimacion_pka_RM1_con_aminoacidos}% <-- avoid accents in labels

\centering

\begin{tabular}{
  l
  S[table-format=1.2]
  S[table-format=-1.1]
  S[table-format=1.1]
  S[table-format=-1.1]
  S[table-format=-1.1]
}
\toprule
& & \multicolumn{4}{c}{RM1} \\
\cmidrule(lr){3-6}
& & \multicolumn{2}{c}{COSMO} & \multicolumn{2}{c}{SS-COSMO} \\
\cmidrule(lr){3-4} \cmidrule(lr){5-6}
 & {\pKa{exp} (\SI{298}{K})}
 & {\pKa{calc}}
 & {\DpKa}
 & {\pKa{calc}}
 & {\DpKa}
\\
\midrule
\textit{Ácidos} \\ 
acético          & 4.75 &   2.1 &   2.6 &   4.2 &   0.6 \\
fluoroacético    & 2.59 &  -0.8 &   3.3 &  -0.8 &   3.4 \\
fórmico\tnote{a} & 3.75 & {ref} & {ref} & {ref} & {ref} \\
pirúvico         & 2.39 &  -3.0 &   5.4 &   0.7 &   1.7 \\
glioxílico       & 3.18 &  -2.3 &   5.5 &   0.4 &   2.8 \\
propanoico       & 4.86 &   2.3 &   2.5 &   3.9 &   0.9 \\
butanoico        & 4.83 &   2.6 &   2.3 &   4.2 &   0.7 \\
acrílico         & 4.25 &   2.0 &   2.3 &   1.0 &   3.3 \\
láctico          & 3.86 &   0.7 &   3.2 &   5.0 &  -1.2 \\
benzoico         & 4.2  &   1.1 &   3.1 &   1.6 &   2.6 \\
\midrule
MAE              &      &       &   3.1 &       &   1.6 \\
\bottomrule
\end{tabular}
\begin{tablenotes}
\footnotesize
\item[a] Desprotonación de referencia
\item[b] Sin valor experimental
\item Estimación y comparación de \pKa{} calculados con RM1 y dos estrategias 
de solvatación: implícita (COSMO) y explícita-implícita(Solvateshell-COSMO). 
El \DpKa{} se realizó como $\DpKa=\pKa{exp}-\pKa{calc}$. La sigla SS significa
Solvateshell.
\end{tablenotes}
\end{threeparttable}

\end{table}

\end{document}

Answer 3

Some more improvements. I think this kind of table is more readable with alternate row colours. Also, pKa should be typed in roman characters:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{booktabs, makecell}
\usepackage{siunitx}
\usepackage[table, svgnames]{xcolor}
\usepackage{amsmath}
\DeclareMathOperator{\pKa}{pKa}

\begin{document}


\begin{table}
  \centering
\rowcolors*{8}{Gainsboro!50!Lavender}{Gainsboro!40!Lavender!40!white}
  \begin{tabular}{ l *{5}{S[table-format=-1.2]}}
\toprule
& & \multicolumn{4}{c}{RM1} \\
\cmidrule(l{2.6em}r{1.9em}){3-6}
& & \multicolumn{2}{c}{COSMO} & \multicolumn{2}{c}{SS-COSMO} \\
\cmidrule(r{5pt}){3-4}\cmidrule(l{5pt}){5-6}
& {\makecell{$\pKa_{\text{exp}}$\\ (\SI{298}{K})}} & {$\pKa_{\text{calc}}$} & {$\Delta(\pKa)$} & {$\pKa_{\text{calc}}$} & {$\Delta(\pKa)$} \\
 \midrule
 \hspace*{-\tabcolsep}\textbf{Ácidos}\smallskip \\
cloroacético & 2.85 & 0.5 & 2.4 & 1.4 & 1.5 \\
4-clorobutírico & 4.52 & 5.0 & -0.5 & 4.7 & -0.2 \\
2-cloropentanoico & & -2.3 & & 1.0 & \\
2-clorobutírico & 2.86 & 0.6 & 2.2 & 0.4 & 2.5 \\
3-clorobutírico & 4.05 & 3.7 & 0.4 & 3.8 & 0.3 \\
acetoacético & 3.6 & 3.4 & 0.2 & 2.0 & 1.6 \\
bromoacético & 2.69 & 1.2 & 1.5 & 1.1 & 1.6 \\
dicloro-acético & 1.41 & -3.2 & 4.6 & -2.5 & 3.9 \\
iodoacético & 3.12 & 2.1 & 1.1 & 2.8 & 0.3 \\
L-valina & 2.29 & -1.9 & 4.2 & 2.6 & -0.3 \\
L-alanina & 2.34 & -1.6 & 3.9 & 2.3 & 0.0 \\
trichloroacético & 0.7 & -7.0 & 7.7 & -4.7 & 5.4 \\
2-chloropropanoico & 2.83 & 0.8 & 2.0 & 0.2 & 2.6 \\
3-chloropropanoico & 3.98 & 3.4 & 0.6 & 5.2 & -1.3 \\
3-hidroxipropanoico & 4.51 & 3.8 & 0.8 & 3.5 & 1.0 \\
acético & 4.75 & {ref} & {ref} & {ref} & {ref} \\
fluoroacético & 2.59 & 1.9 & 0.7 & -0.3 & 2.9 \\
fórmico & 3.75 & 6.4 & -2.6 & 4.3 & -0.6 \\
pirúvico & 2.39 & -0.3 & 2.7 & 1.3 & 1.1 \\
glioxílico & 3.18 & 0.3 & 2.9 & 1.0 & 2.2 \\
propanoico & 4.86 & 4.9 & -0.1 & 4.5 & 0.3 \\
butanoico & 4.83 & 5.2 & -0.3 & 4.7 & 0.1 \\
acrílico & 4.25 & 4.6 & -0.3 & 1.5 & 2.7 \\
láctico & 3.86 & 3.3 & 0.6 & 5.6 & -1.7 \\
benzoico & 4.2 & 3.7 & 0.5 & 2.2 & 2.0 \\[-\aboverulesep]
\midrule
\hiderowcolors MAE & & & 1.8 & & 1.7\\
\bottomrule
\end{tabular}
\end{table}

\end{document}