The K-alpha, K-beta, and total K X-rays fluorescence cross-sections, as well as the average fluorescence yields for six elements with 16 <= Z <= 23 have been measured at 5.96 keV. The areas of the K-alpha and K-beta spectral peaks, as well as the net peak areas, have been determined by a fitting process. Furthermore, the I-K beta/I-K alpha intensity ratios for these elements have been investigated. The K X-rays emitted by samples have been counted by a Si(Li) detector. Experimental values of the K X-ray fluorescence cross-sections, fluorescence yields, and the I-K beta/I-K alpha intensity ratios have been compared with theoretical values. In most cases, there is an agreement between the experimental and theoretical values within the standard uncertainties. (c) 2004 Elsevier Ltd. All rights reserved.