\begin{table}%t2
\par
\caption{Low-$k$ FSDP feature positions with corresponding real-space distances and short-range order bond length.\label{tab2}}         % title of Table
%\centering
                          % used for centering table
\begin{tabular}{r c c c c}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
Sample & Feature & $k$          & $D=2\pi k^{-1}$  & $r=2.5k^{-1}$   \\    % table heading 
       & & (\AA$^{-1}$) & (\AA)           & (\AA) \\
\hline
   a-SiO$_{2}$ & & 1.603 & 3.92 & 1.56     \\
\hline
   Product I & & &  &  \\ 
       Un & (1) & 1.505 & 4.17 & 1.66 \\
          & (2) & 1.904 & 3.30 & 1.31 \\
          & (3) & 2.477 & 2.54 & 1.01 \\
    900 K & (1) & 1.510 & 4.16 & 1.66 \\
          & (2) & 1.851 & 3.39 & 1.35 \\
          & (3) & 2.472 & 2.54 & 1.01 \\
\hline
   Product II & & &  &     \\ 
          Un & (1) & 1.447 & 4.34 & 1.73 \\
             & (2) & 1.921 & 3.27 & 1.30 \\
             & (3) & 2.479 & 2.53 & 1.01 \\
      1000 K & (1) & 1.425 & 4.41 & 1.75 \\
             & (2) & 1.924 & 3.27 & 1.30 \\
      1300 K & (2) & 1.826 & 3.44 & 1.37 \\
             & (3) & 2.426 & 2.59 & 1.03 \\
\hline
   Product III  & & &  &     \\ 
            Un & & 1.829 & 3.44 & 1.37 \\
        1000 K & & 1.749 & 3.59 & 1.43 \\
        1300 K & & 1.661 & 3.78 & 1.51 \\
\hline                                   %inserts single line
\end{tabular}
\end{table}