title: Using environments for table generation - "Misplaced alignment tab character" error
body: <p>I am trying to create a set of simple environments to make the creation of tables a bit easier and consistent.
  The environment <code>\observation</code> generates the empty table. Rows of observations are introduced by the command <code>\subobservation</code>. It works with one <code>\subobservation</code> command but I cannot figure out how to insert multiple rows.
  With the following code sample I get an "Misplaced alignment tab character" error.</p>
  
  <pre><code>\documentclass[11pt,a4paper]{article}
  \usepackage{lipsum}
  
  \newenvironment{observationtable}{
      \begin{center}
      \begin{tabular}{p{0.2\textwidth}p{0.6\textwidth}p{0.2\textwidth}}
      \hline\\
      }
      { 
      \end{tabular} 
      \end{center}
  }
  
  \newcommand{\subobservation}[3]{
      \textbf{#1} &amp; #2 &amp; \textbf{#3} \\
      \hline\\
      }
  
  \newenvironment{observation}[1]{
      \textbf{#1}
      \begin{observationtable}
          1st Col &amp; 2nd Col &amp; 3rd Col \\
          \hline\\
      }{
      \end{observationtable}
      }
  
  \begin{document}
  
  \begin{observation}
      {An interesting collection of observation}
     \begin{subobservation}
          {some information}
          {\lipsum[1]}
          {another something}
      \end{subobservation}
  
      \begin{subobservation}
          {some 2nd information}
          {\lipsum[2]}
          {another 2nd something}
      \end{subobservation}
  
  \end{observation}
  
  \end{document}
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/39JWH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/39JWH.png" alt="pdfLaTeX output for described problem"></a></p>