\begin{table}%t18
%%\centering

\par
\caption{\label{Solid phase reactions used for complex molecule formation}Solid phase reactions used for complex molecule formation.}
\begin{tabular}{llllll} 
\hline\hline\noalign{\smallskip}
& Reactant1        & Reactant2  & Product1         & Product2 & Activation       \\
&                  &            &                  &          & Energy $E_a$ (K) \\
\hline
1   & $*$C             & $*$CO      & $*$CCO           &          & $5.0 \times 10^2$ \\   
2   & $*$C             & $*$CO      & $*$COC           &          & $5.0 \times 10^2$ \\   
3   & $*$C             & $*$H       & $*$CH            &          & 0.0 \\   
4   & $*$C             & $*$N       & $*$CN            &          & 0.0 \\   
5   & $*$C             & $*$NH      & $*$HNC           &          & 0.0 \\   
6   & $*$C             & $*$NH$_2$  & $*$H             & $*$HNC   & 0.0 \\   
7   & $*$C             & $*$O       & $*$CO            &          & 0.0 \\   
8   & $*$C             & $*$O$_2$   & $*$CO            & $*$O     & 0.0 \\   
9   & $*$C             & $*$OH      & $*$CO            & $*$H     & 0.0 \\   
10  & $*$C             & $*$OH      & $*$COH           &          & 0.0 \\   
11  & $*$C$_2$H$_3$O   & $*$H       & $*$CH$_3$CHO     &          & 0.0 \\   
12  & $*$C$_2$H$_5$O   & $*$H       & $*$C$_2$H$_5$OH  &          & 0.0 \\   
13  & $*$C$_2$HO       & $*$H       & $*$CH$_2$CO      &          & 0.0 \\   
14  & $*$CCO           & $*$H       & $*$C$_2$HO       &          & 0.0 \\   
15  & $*$CH            & $*$H       & $*$CH$_2$        &          & 0.0 \\   
16  & $*$CH            & $*$O       & $*$HCO           &          & 0.0 \\   
17  & $*$CH            & $*$OH      & $*$CHOH          &          & 0.0 \\   
18  & $*$CH$_2$        & $*$H       & $*$CH$_3$        &          & 0.0 \\   
19  & $*$CH$_2$        & $*$O       & $*$H$_2$CO       &          & 0.0 \\   
20  & $*$CH$_2$        & $*$OH      & $*$CH$_2$OH      &          & 0.0 \\   
21  & $*$CH$_2$CO      & $*$H       & $*$C$_2$H$_3$O   &          & 0.0 \\   
22  & $*$CH$_2$OC      & $*$H       & $*$CH$_3$OC      &          & 0.0 \\   
23  & $*$CH$_2$OH      & $*$H       & $*$CH$_3$OH      &          & 0.0 \\   
24  & $*$CH$_3$        & $*$H       & $*$CH$_4$        &          & 0.0 \\   
25  & $*$CH$_3$        & $*$O       & $*$CH$_3$O       &          & 0.0 \\   
26  & $*$CH$_3$        & $*$OH      & $*$CH$_3$OH      &          & 0.0 \\   
27  & $*$CH$_3$CHO     & $*$H       & $*$C$_2$H$_5$O   &          & 0.0 \\   
28  & $*$CH$_3$O       & $*$H       & $*$CH$_3$OH      &          & 0.0 \\   
29  & $*$CH$_3$OC      & $*$H       & $*$CH$_3$OCH     &          & 0.0 \\   
30  & $*$CH$_3$OCH     & $*$H       & $*$CH$_3$OCH$_2$ &          & 0.0 \\   
31  & $*$CH$_3$OCH$_2$ & $*$H       & $*$CH$_3$OCH$_3$ &          & 0.0 \\   
32  & $*$CHOC          & $*$H       & $*$CH$_2$OC      &          & 0.0 \\   
33  & $*$CHOH          & $*$H       & $*$CH$_2$OH      &          & 0.0 \\   
34  & $*$CN            & $*$H       & $*$HCN           &          & 0.0 \\   
35  & $*$CO            & $*$H       & $*$COH           &          & $3.0 \times 10^3$ \\   
36  & $*$CO            & $*$H       & $*$HCO           &          & $1.0 \times 10^3$ \\   
37  & $*$CO            & $*$OH      & $*$CO$_2$        & $*$H     & $3.0 \times 10^2$ \\   
38  & $*$COC           & $*$H       & $*$CHOC          &          & 0.0 \\   
39  & $*$COH           & $*$H       & $*$CHOH          &          & 0.0 \\   
40  & $*$H             & $*$H       & $*$H$_2$         &          & 0.0 \\   
41  & $*$H             & $*$H$_2$CO & $*$H$_2$         & $*$HCO   & $1.85 \times 10^3$ \\   
42  & $*$H             & $*$HCO     & $*$CO            & $*$H$_2$ & 0.0 \\   
43  & $*$H             & $*$N       & $*$NH            &          & 0.0 \\   
44  & $*$H             & $*$NH      & $*$NH$_2$        &          & 0.0 \\   
45  & $*$H             & $*$NH$_2$  & $*$NH$_3$        &          & 0.0 \\   
46  & $*$H             & $*$NO      & $*$HNO           &          & 0.0 \\   
47  & $*$H             & $*$O       & $*$OH            &          & 0.0 \\   
48  & $*$H             & $*$OH      & $*$H$_2$O        &          & 0.0 \\   
49  & $*$HCO           & $*$O       & $*$CO            & $*$OH    & 0.0 \\   
50  & $*$HCO           & $*$O       & $*$CO$_2$        & $*$H     & $2.0 \times 10^1$ \\   
51  & $*$N             & $*$O       & $*$NO            &          & 0.0 \\   
52  & $*$N             & $*$OH      & $*$HNO           &          & 0.0 \\   
53  & $*$NH            & $*$O       & $*$HNO           &          & 0.0 \\   
54  & $*$O             & $*$O       & $*$O$_2$         &          & 0.0 \\   
\hline
\end{tabular}
\vspace*{2mm}
\end{table}