To investigate the effects of introducing the iron compound on the carbonization behavior polyacrylonitile (PAN)-based electrospun nanofibers were carbonized with or without iron(III) acetylacetonate (AAI) over the temperature range of 900-1500 degrees C in nitrogen atmosphere. The morphological characteristics of the carbon nanotibers were investigated using X-ray diffractometer (XRD), Raman spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The electrical conductivity of the carbon nanofiber web was measured by four-point probe method. The iron catalyst had a profound effect on the crystal structure of the carbonized nanofiber. In the presence of AAI the nanofibers carbonized at 1300 degrees C developed graphite structure, which could be obtained at the temperature higher than 2000 degrees C in the absence of the catalyst. The in-plane size of the graphite crystals (L-a) was measured to be about 6.5 nm by Raman spectroscopy and the (0 0 2) spacing by XRD was 0.341 nm. (c) 2005 Elsevier B.V. All rights reserved.