Chemical abundances in Seyfert galaxies -- VII. Direct abundance determination of neon based on optical and infrared emission lines.

For the first time, neon abundance has been derived in the narrow line region from a sample of Seyfert~2 nuclei. In view of this, we compiled from the literature fluxes of optical and infrared (IR) narrow emission lines for 35 Seyfert 2 nuclei in the local universe ($z 8.80$]) an increase in Ne/O with O/H is found, which likely indicates secondary stellar production for the neon.