In this study, nylon-6 nanofiber mats containing Fe super(2+) ions were fabricated via electrospinning. The resultant electrospun nylon-6/FeCl sub(2) nanofiber mats were characterized by SEM, TEM, Fourier transform IR spectroscopy, wide angle XRD and DSC. Unique morphological features, such as spider's-web-like morphologies, were observed and became evident with increasing additive Fe super(2+) ions. The metastable gamma form was predominant in the as-spun nylon-6 nanofibers. The relative intensity of such gamma form gradually decreased with increasing additive Fe super(2+) ions, indicative of transformation of the crystalline structure in the electrospun nylon-6/FeCl sub(2) nanofibers due to strong molecular interactions between the nylon-6 backbone and the additive Fe super(2+) ions. The effects of additive Fe super(2+) ions on the mechanical properties of both nonwoven nanofiber mats and single nanofibers were investigated. In particular, Young's modulus of nylon-6/FeCl sub(2) single nanofibers gradually increased from 1.46 to 5.26 GPa with increasing additive Fe super(2+) ions. copyright 2013 Society of Chemical Industry The crystallinity and mechanical properties of the nylon-6/FeCl sub(2) nanofibers were significantly influenced by the Fe super(2+)-ion additives. Unique morphological features, such as spider-net like morphologies, were observed at higher sub(Fe) ( greater than or equal to 15 wt%).