\begin{table}%[!p]%t6{llcl}
\caption{Ionic abundances from CELs. \label{cel_ab}}
\begin{tabular}{llcl}
\hline\hline\noalign{\smallskip}
{Ion} & {$\lambda$} & {$I(\lambda)$}&
{$N$(X$^{i+}$)/$N$(H$^+$)} \\
 & {({\AA})} &
{[$I({\rm H}\beta)=100$]} & \\
\hline\noalign{\smallskip}
C$^{+}$& 2324&177$^{a}$& $8.74\times10^{-5}$\\
        &15.8~$\mu$m&2.4&$5.36\times10^{-4}$\\
&adopted&& $8.74\times10^{-5}$\\
C$^{2+}$&1908&726&$3.85\times10^{-4}$\\
C$^{3+}$&1550&1125&$4.18\times10^{-4}$\\
N$^+$&5754&5.76&$1.60\times10^{-5}$\\
    &6548&33.1& $1.53\times10^{-5}$\\
    &6584&93.6& $1.47\times10^{-5}$\\
    &122~$\mu$m&0.028&$2.01\times10^{-5}$\\
&adopted&& $1.49\times10^{-5}$\\
N$^{2+}$&1750&27.1&$6.01\times10^{-5}$\\
        &57~$\mu$m&0.99&$4.30\times10^{-5}$\\
&adopted&& $5.95\times10^{-5}$\\
N$^{3+}$&1485&42.3&$4.85\times10^{-5}$\\
N$^{4+}$&1240& 35.9&$1.46\times10^{-5}$\\
O$^+$&2470&25.9&$5.05\times10^{-5}$\\
  &3726&20.8&$3.19\times10^{-5}$\\
  &3729&7.51&$3.17\times10^{-5}$\\
  &7320&17.9&$4.72\times10^{-5}$\\
  &7330&14.7&$4.82\times10^{-5}$\\
&adopted&&$4.33\times10^{-5}$\\
O$^{2+}$&1663&34.5&$2.56\times10^{-4}$\\
  &4363&25.4& $3.07\times10^{-4}$\\
  &4931&0.254&$3.33\times10^{-4}$\\
  &4959&564.0&$3.03\times10^{-4}$\\
  &5007&1657.92&$3.08\times10^{-4}$\\
  &52~$\mu$m&6.86& $1.63\times10^{-4}$\\
  &88~$\mu$m&0.79& $1.83\times10^{-4}$\\
&adopted&&$3.06\times10^{-4}$\\
O$^{3+}$&1400&49.5$^{b}$ &$1.39\times10^{-4}$\\
        &26~$\mu$m&40.2&$6.63\times10^{-5}$\\
&adopted&&$6.63\times10^{-5}$\\
Ne$^+$&12.8~$\mu$m&5.33&$7.16\times10^{-6}$\\
Ne$^{2+}$&3869&125.8&$5.37\times10^{-5}$\\
         &36~$\mu$m& 2.82&$4.25\times10^{-5}$\\
&adopted&&$5.35\times10^{-5}$\\
Ne$^{3+}$&1602&13.8&$3.30\times10^{-5}$\\
   &2422&120.4&$4.32\times10^{-5}$\\
   &2425&41.3& $4.15\times10^{-5}$\\
   &4714&0.903&$2.82\times10^{-5}$\\
   &4715&0.257 &$2.87\times10^{-5}$\\
   &4724&0.807& $2.31\times10^{-5}$\\
   &4726&0.677& $2.22\times10^{-5}$\\
&   adopted&&$4.19\times10^{-5}$\\
Ne$^{4+}$&3346&38.0& $2.02\times10^{-5}$\\
   &14.3~$\mu$m&72.2&$1.23\times10^{-5}$\\
&adopted&&$1.50\times10^{-5}$\\
S$^+$&4068&7.61&$5.06\times10^{-7}$\\
   &4076&2.44&  $4.85\times10^{-7}$\\
   &6716&1.72&  $6.56\times10^{-7}$\\
 &6731&3.88&$6.78\times10^{-7}$\\
&adopted&&$5.62\times10^{-7}$\\
S$^{2+}$&6312&4.23&$3.46\times10^{-6}$\\
&8830&0.011&$3.51\times10^{-6}$\\
\hline
   &33.5~$\mu$m&0.494&$2.13\times10^{-6}$\\
   &18.7~$\mu$m&4.69&$2.18\times10^{-6}$\\
&adopted&&$2.75\times10^{-6}$\\
S$^{3+}$&10.5~$\mu$m&22.7&$1.56\times10^{-6}$\\
Cl$^{+}$&8578&0.324&$2.08\times10^{-8}$\\
    &9124&0.14&$3.40\times10^{-8}$\\
&adopted&&$2.48\times10^{-8}$\\
 Cl$^{2+}$&3353&0.099&$4.55\times10^{-8}$\\
          &5518&0.189&$5.40\times10^{-8}$\\
  &8434&0.074&$7.70\times10^{-8}$\\
           &8481&0.073&$7.81\times10^{-8}$\\
  &adopted&&$5.96\times10^{-8}$\\
  Cl$^{3+}$&5324&0.06&$6.07\times10^{-8}$\\
          &7531&0.457&$5.74\times10^{-8}$\\
          &8045&1.05& $5.69\times10^{-8}$\\
          &11.8~$\mu$m&0.46&$1.01\times10^{-7}$\\
&  adopted&&$6.71\times10^{-8}$\\
 Cl$^{4+}$&6.7~$\mu$m&0.365&$1.08\times10^{-8}$\\
 Ar$^+$   &7.0~$\mu$m&1.726&$1.43\times10^{-7}$\\
 Ar$^{2+}$&7136&21.4&$1.09\times10^{-6}$\\
          &7751&4.65&$9.79\times10^{-7}$\\
          &9.0~$\mu$m&6.26&$6.82\times10^{-7}$\\
          &21.9~$\mu$m&0.339&$9.20\times10^{-7}$\\
 &adopted&&$9.94\times10^{-7}$\\
 Ar$^{3+}$&4712&2.21&$5.84\times10^{-7}$\\
          &4741&8.11&$6.45\times10^{-7}$\\
 &adopted&&$6.32\times10^{-7}$\\
 Ar$^{4+}$&4626&0.07&$1.63\times10^{-7}$\\
          &6435&1.31&$1.99\times10^{-7}$\\
          &7.9~$\mu$m&2.50&$1.31\times10^{-7}$\\
 &adopted&&$1.54\times10^{-7}$ \\
 Ar$^{5+}$&4.5~$\mu$m&6.88&$8.58\times10^{-8}$\\
 Mg$^{3+}$&4.4~$\mu$m&8.67&$3.65\times10^{-6}$\\
 Mg$^{4+}$&2783&9.53&$1.39\times10^{-5}$\\
          &2929&3.39&$1.27\times10^{-5}$\\
          & 5.6~$\mu$m&22.1&$9.88\times10^{-6}$\\
 &adopted&&$1.18\times10^{-5}$\\
 Fe$^{2+}$&4702&0.067&$3.09\times10^{-8}$\\
          &4734&0.032&$2.97\times10^{-8}$\\
          &4755&0.032&$3.88\times10^{-8}$\\
          &4770&0.023&$3.07\times10^{-8}$\\
          &4778&0.018&$3.46\times10^{-8}$\\
      &4881&0.069$^{c}$&$1.77\times10^{-8}$\\
          &5270&0.094&$3.70\times10^{-8}$\\
 &adopted&&$3.40\times10^{-8}$\\
 Fe$^{3+}$&6740&0.015&$7.08\times10^{-8}$\\
          &7183&0.016&$3.93\times10^{-7}$\\
          &7189&0.029&$3.73\times10^{-7}$\\
 &adopted&&$3.02\times10^{-7}$\\
 Fe$^{5+}$&5234&0.020&$1.19\times10^{-9}$\\
          &5278&0.035&$1.24\times10^{-9}$\\
          &5335&0.102&$1.97\times10^{-9}$\\
          &5425&0.117&$1.56\times10^{-9}$\\
\hline
          &5484&0.070&$2.44\times10^{-9}$\\
          &5631&0.083&$1.35\times10^{-9}$\\
  &adopted&&$1.73\times10^{-9}$\\
 Fe$^{6+}$&4894&0.062&$1.05\times10^{-9}$\\
          &4989&0.089&$1.68\times10^{-9}$\\
          &5159&0.145&$1.75\times10^{-9}$\\
          &adopted&&$1.56\times10^{-9}$\\\hline
\end{tabular}
\medskip
$^{a}$ Corrected for a $4\%$ contribution from the [\ion{O}{iii}]
  $\lambda$2322 line, assuming [\ion{O}{iii}] $I(\lambda2322)/(\lambda1663)=0.14$.\\
$^{b}$ Blended with the \ion{Si}{iv} $\lambda$1400 line.\\
$^{c}$ Probably underestimated because of absorption by the
    DIB at 4882.56~{\AA}.
\end{table}