Chemical effects on the L X-ray production cross-sections (alpha(Ll), sigma(L proportional to), sigma(L beta), and sigma(L gamma)) and the average fluorescence yield (omega(L)) for Hf compounds were investigated. In this study, the samples were excited by 123.6 keV gamma-rays from a Co-57 annular radioactive source. L X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. We observed a chemical effect on the L X-ray cross-sections and average fluorescence yield for Hf compounds. However, the sigma(Ll) cross-section; dependence on the chemical state of Hf compounds is almost negligible. The experimental values have been compared with the theoretically calculated values of pure Hf. (c) 2007 Elsevier B.V. All rights reserved.