\begin{table}%t8
\caption{\label{abun-com}Comparison of the derived molecular fractional abundances with other published results.}
%\centering
\par
\begin{tabular}{c c c c c c c c c c}    
\hline\hline \noalign{\smallskip}               
          &  CS & HCN & SiO & SiS  & SO & SO$_2$  & CN \\
\hline
This work (case A) &  3.0 $\times$ 10$^{-7}$ &
1.4 $\times$ 10$^{-6}$ & 1.3 $\times$ 10$^{-5}$ & 1.3 $\times$ 10$^{-6}$ &
7.8 $\times$ 10$^{-7}$ &  1.4 $\times$ 10$^{-5}$     & 1.6 $\times$ 10$^{-7}$    \\
This work (case B) & 8.1 $\times$ 10$^{-8}$ &
4.3 $\times$ 10$^{-7}$ & 5.1 $\times$ 10$^{-6}$ & 3.7 $\times$ 10$^{-7}$ & 2.7 $\times$ 10$^{-7}$ &  4.2 $\times$ 10$^{-6}$    & 5.1 $\times$ 10$^{-8}$      \\
 (1) &  1.0 $\times$ 10$^{-7}$ & 9.8 $\times$ 10$^{-7}$ & 1.7 $\times$ 10$^{-5}$ & 4.4 $\times$ 10$^{-7}$ & 2.6 $\times$ 10$^{-6}$ &  --     & --       \\
 (2) &  3.0 $\times$ 10$^{-7}$ & 6.0 $\times$ 10$^{-7}$ & --  & 7.0 $\times$ 10$^{-7}$ & -- & --      & --    \\
 (3) &  -- & --  & 3.0 $\times$ 10$^{-6}$ & -- & 1.8 $\times$ 10$^{-6}$ &  4.1 $\times$ 10$^{-6}$      & --   \\
\hline
 (4) &   2.9 $\times$ 10$^{-7}$  &  1.4 $\times$ 10$^{-7}$   & 3.2 $\times$ 10$^{-5}$ &  3.5 $\times$ 10$^{-6}$  & 9.1 $\times$ 10$^{-7}$ &  2.2 $\times$ 10$^{-7}$ & $3\times10^{-7}$    \\
 (5) &   2.8 $\times$ 10$^{-7}$  &  2.1 $\times$ 10$^{-6}$   & 3.8 $\times$ 10$^{-5}$ &  3.8 $\times$ 10$^{-10}$  & 7.8 $\times$ 10$^{-8}$ &  --    & $2.4\times10^{-10}$      \\
\hline      
\end{tabular}
\tablefoot{In the first part, we list results derived from an observational analysis, in the second part theoretical predictions from chemical models. Abundances from the chemical models by \citet{Duari1999} were selected
at a radius of $2.2R_{*}$ ($5\times10^{13}$ cm).}
\tablebib{(1)~\citet{Bujarrabal1994}; (2) \citet{Lindqvist1988}; (3) \cite{Omont1993}; (4) \citet{Willacy1997}; (5) \citet{Duari1999}.}
\end{table}