\begin{table}%t4
\caption{Composition of the silicate mixture at 3 and 20 AU in a stationary
protoplanetary disc model with $\dot M=1\times10^{-7}~M_{\odot}$~yr$^{-1}$.
The numbers are fractions of the silicon contained in the different dust
species. "cr'' and "am'' denote crystalline dust or amorphous dust with a
composition like that of the indicated crystalline material, respectively.}\label{TabMetCom}
%\centering
\par
\begin{tabular}{ccccccccccccccccc}
\hline
\hline
 $r$ && \multicolumn{3}{c}{olivine} && forsterite &&
     \multicolumn{3}{c}{pyroxene} && enstatite &&
     \multicolumn{3}{c}{quartz} \\
 AU  &\hspace*{.3cm}& cr &\hspace*{.3cm}& am &\hspace*{.3cm}& cr &
\hspace*{.3cm}& cr &\hspace*{.3cm}& am &\hspace*{.3cm}&
  cr &\hspace*{.3cm}& cr &\hspace*{.3cm}& am\\
\hline
3 && 0.159 && 0.158 && 0.037 && 0.067 && 0.070 && 0.458 && 0.023 && 0.027 \\
20&& 0.073 && 0.469 && 0.010 && 0.031 && 0.202 && 0.129 && 0.011 && 0.076 \\
\hline
\end{tabular}
\end{table}