7026, and $\lambda$4661 for H 1-41 and M 3-32. Some PNe show lines from higher iron ionization states; this will be discussed in § \[withoutICF\].

Table \[tab:2\] presents all the computed ionic abundances and their uncertainties. The last column shows the number of \[\] lines used to derive the Fe$^{++}$ abundance in each object. The PNe where only upper limits are available are distinguished either with “1?”, when the $\lambda$4658 line was used (note that this line could be a misidentification of \[\] $\lambda$4658), or with “–” when $\lambda$4661 was used.

[lllllllc]{} Cn 1-5 & $11.08\pm0.02$ & – & $8.36\pm0.11$ & $8.68\pm0.04$ & 5.23 & $6.29^{+0.05}_{-0.07}$ & 8\
Cn 3-1 & $10.67\pm0.02$ & $7.52^{+0.11}_{-0.15}$ & $8.68^{+0.12}_{-0.09}$ & $7.26^{+0.11}_{-0.08}$ & – & $5.57^{+0.06}_{-0.05}$ & 3\
DdDm 1 & $10.95\pm0.02$ & – & $7.38^{+0.31}_{-0.14}$ & $7.91^{+0.05}_{-0.04}$ & – & $5.76^{+0.08}_{-0.04}$ & 4\
H 1-41 & $10.96\pm0.02$ & $10.35\pm0.02$ & $7.27^{+0.19}_{-0.14}$ & $8.50\pm0.04$ & – & $<4.85$ & –\
H 1-42 & $11.05\pm0.02$ & $8.83\pm0.02$ & $7.10^{+0.23}_{-0.18}$ & $8.54\pm0.04$ & 4.50 & $4.67^{+0.17}_{-0.14}$ & 3\
H 1-50 & $10.99\pm0.02$ & $10.04\pm0.02$ & $7.50^{+0.12}_{-0.10}$ & $8.62\pm0.04$ & – & $4.54^{+0.10}_{-0.11}$ & 1\
Hu 1-1 & $10.93\pm0.02$ & $10.18\pm0.02$ & $8.00^{+0.06}_{-0.05}$ & $8.40\pm0.04$ & – 