Vertical alignment in table

Question

I am making a table with LaTeX, and I have trouble with vertical alignment of the texts. When I have \hline, the text crosses the line.

Here is the code:

\begin{tabular}{lcccc}
\hline\hline
 & \textbf{$d_{(O_{1}-Zn/Mg)}(\SI{}{\angstrom})$} 
 & \textbf{$d_{(O_{2}-Zn/Mg)}(\SI{}{\angstrom})$} 
 & \textbf{$d_{(O_{3}-Zn/Mg)}(\SI{}{\angstrom})$} 
 & \textbf{$d_{(O_{\bot}-Zn/Mg)}(\SI{}{\angstrom})$} \\[1mm]
\hline 
\textbf{Pure HB-NWs} &  &  &  &   \\
\hline\hline
\end{tabular}

Also I enclosed the undesired result to make my point clear. Please let me know how I can solve this problem.

Answer 1

There are a few problems with your table:

• You shouldn't use \hline. Instead, use \...rule from the booktabs package.
• Putting \textbf around a math expression has no effect; if you want bold math, use \mtathbf.
• If you use \ce from the mhchem package when typesetting chemical elements, you get the correct output.
• Here, use \unit{<unit>} instead of \SI{<number>}{<unit>}.
• The subscripts, say (O_{1} - \ce{Zn}/\ce{Mg}) (after my edit), look wierd. What is the exact meaning of this? (It depends on how it should be typeset.)

Here is how I would typeset the table:

\documentclass{article}

\usepackage[margin = 3cm]{geometry} % to avoid `overfull \hbox'
\usepackage[version = 4]{mhchem}
\usepackage{booktabs}
\usepackage{siunitx}

\begin{document}

\begin{tabular}{l *{4}{c}}
  \toprule
    & $d_{(O_{1} - \ce{Zn}/\ce{Mg})}(\unit{\angstrom})$
    & $d_{(O_{2} - \ce{Zn}/\ce{Mg})}(\unit{\angstrom})$
    & $d_{(O_{3} - \ce{Zn}/\ce{Mg})}(\unit{\angstrom})$
    & $d_{(O_{\bot} - \ce{Zn}/\ce{Mg})}(\unit{\angstrom})$ \\
  \midrule
    \textbf{Pure HB-NWs} & & & & \\
  \bottomrule
\end{tabular}

\end{document}

Or maybe

\documentclass{article}

\usepackage[margin = 4cm]{geometry} % to avoid `overfull \hbox'
\usepackage[version = 3]{mhchem}
\usepackage{booktabs}
\usepackage{siunitx}

\begin{document}

\begin{tabular}{l *{4}{c}}
  \toprule
     & $d_{(O_{1} - \ce{Zn}/\ce{Mg})}$
     & $d_{(O_{2} - \ce{Zn}/\ce{Mg})}$
     & $d_{(O_{3} - \ce{Zn}/\ce{Mg})}$
     & $d_{(O_{\bot} - \ce{Zn}/\ce{Mg})}$ \\[0.5ex]
     & \unit{\angstrom}
     & \unit{\angstrom}
     & \unit{\angstrom}
     & \unit{\angstrom} \\
  \midrule
    \textbf{Pure HB-NWs} & & & & \\
  \bottomrule
\end{tabular}

\end{document}

P.S. TeXstudio is the editor; that has nothing to do with your table.

Answer 2

The package booktabs changes the spacing between lines and the table cells. It uses the commands \toprule and \bottomrule for thicker lines (you used a double \hline for it) and midrule inside the table. Vertical lines are problematic in booktabs and this solution somewhat changes your layout, but maybe it helps:

\documentclass{article}

\usepackage{siunitx}
\usepackage{booktabs}

\begin{document}

\begin{tabular}{lcccc}
\toprule
 & \textbf{$d_{(O_{1}-Zn/Mg)}(\SI{}{\angstrom})$} 
 & \textbf{$d_{(O_{2}-Zn/Mg)}(\SI{}{\angstrom})$} 
 & \textbf{$d_{(O_{3}-Zn/Mg)}(\SI{}{\angstrom})$} 
 & \textbf{$d_{(O_{\bot}-Zn/Mg)}(\SI{}{\angstrom})$} \\[1mm]
\midrule
\textbf{Pure HB-NWs} &  &  &  &   \\
\bottomrule
\end{tabular}

\end{document}

Answer 3

You can set extrarowheight with the help of array package.

\documentclass{article}
\usepackage{siunitx}
\usepackage{array}
\setlength{\extrarowheight}{2pt} %% adjust suitably
\begin{document}
  \begin{tabular}{lcccc}
\hline\hline
 & \textbf{$d_{(O_{1}-Zn/Mg)}(\SI{}{\angstrom})$}
 & \textbf{$d_{(O_{2}-Zn/Mg)}(\SI{}{\angstrom})$}
 & \textbf{$d_{(O_{3}-Zn/Mg)}(\SI{}{\angstrom})$}
 & \textbf{$d_{(O_{\bot}-Zn/Mg)}(\SI{}{\angstrom})$} \\[1mm]
\hline
\textbf{Pure HB-NWs} &  &  &  &   \\
\hline\hline
\end{tabular}
\end{document}

Or add an invisible rule in the particular row:

\documentclass{article}
\usepackage{siunitx}
\begin{document}
  \begin{tabular}{lcccc}
\hline\hline
\rule{0ex}{3ex}             %%% adjust 3ex suitably.
 & \textbf{$d_{(O_{1}-Zn/Mg)}(\SI{}{\angstrom})$}
 & \textbf{$d_{(O_{2}-Zn/Mg)}(\SI{}{\angstrom})$}
 & \textbf{$d_{(O_{3}-Zn/Mg)}(\SI{}{\angstrom})$}
 & \textbf{$d_{(O_{\bot}-Zn/Mg)}(\SI{}{\angstrom})$} \\[1mm]
\hline
\textbf{Pure HB-NWs} &  &  &  &   \\
\hline\hline
\end{tabular}
\end{document}