The K/K
X-ray intensity ratios were measured for pure Cr, Mn, Co and Cu belonging to the 3 d shell as well as in their compounds, to look for the influence of the chemical environment on the fluorescence yield ratios. The vacancies in the K shell created by 59.5 keV
-rays from an241Am source and the X-rays were measured using a Ge(Li) detector. A steady increase of the K
/K
intensity ratio was observed with increasing oxidation. The present results agree with previously published experimental data.