\begin{table} %tb10
\caption{\label{tab_abun}Molecular abundances.}
\small%\centering
\par
\begin{tabular}{lllll}
\hline
\hline \noalign{\smallskip}
 Region & Species & X (This work) & X\tablefootmark{5} & X\tablefootmark{6}\\
 & & ($\times$10$^{-8}$) & ($\times$10$^{-8}$) &
 ($\times$10$^{-8}$)\\
\hline
Extended & OCS & 11.7 & $<$0.3 & ...\\
ridge\tablefootmark{1} & HCS$^+$ & 0.005 & 0.02 & ...\\
 & H$_2$CS & 2.7 & 0.11 & ...\\
 & CS & 3.7 & 1.1 & 2.1\\
 & CCS & 0.01 & ... & ...\\
\noalign{\smallskip}
Compact & OCS & 5.5 & 3.0 & ...\\
ridge\tablefootmark{2} & HCS$^+$ & 0.04 & 0.0013 & ...\\
 & H$_2$CS & 0.7 & 0.12 & 0.65\\
 & CS & 3.6 & 1.0 & 4.0\\
 & CCS & 0.0035 & ... & ...\\
\noalign{\smallskip}
Plateau\tablefootmark{3} & OCS & 3.9 & 1.4 & ...\\
 & HCS$^+$ & 0.017 & 0.004 & ...\\
 & H$_2$CS & 0.3 & 0.08 & ...\\
 & CS & 0.7 & 0.4 & 1.2\\
 & CCS & 0.0007 & ... & ...\\
\noalign{\smallskip}
Hot & OCS & 5.2 & 1.1 & 1.7\\
core\tablefootmark{4} & HCS$^+$ & 0.005 & 0.0013 & ...\\
 & H$_2$CS & 0.1 & 0.08 & ...\\
 & CS & 2.0 & 0.6 & 0.29\\
 & CCS & 0.005 & ... & ...\\
 & CCCS & 0.002 & ... & ...\\
\hline 
\end{tabular}
\tablefoot{Derived molecular abundances and comparation with other works.\\
\tablefoottext{1}{Assuming $N$(H$_2$) = 7.5 $\times$ 10$^{22}$~cm$^{-2}$. }
\tablefoottext{2}{Assuming $N$(H$_2$)= 7.5 $\times$ 10$^{22}$~cm$^{-2}$.}
\tablefoottext{3}{Assuming $N$(H$_2$)= 2.1 $\times$ 10$^{23}$~cm$^{-2}$.}
\tablefoottext{4}{Assuming $N$(H$_2$) = $4.2 \times  10^{23}$~cm$^{-2}$.} 
\tablefoottext{5}{From \citet{sut95}.}
\tablefoottext{6}{From \citet{per07}.}}
\end{table}