X-ray anomalous scattering difference patterns in qualitative and quantitative powder diffraction analysis

Difference patterns, obtained using two or more wavelengths to exploit the anomalous scattering of specific elements in the sample, can provide a valuable adjunct to conventional methods of qualitative and quantitative powder diffraction analysis. A preliminary investigation of this method has been made, using a sample containing 6% by weight Co₃O₄ in a matrix of kaolinite [Al₂Si₂O₅(OH)₄]. It was found that, by using Co Kα and Co Kβ radiations, the Bragg reflections from the Co₃O₄ could be isolated and this difference pattern used to make quantitative analyses accurate to ± 1%. These results indicate that for many problems, especially those involving compounds of transition metals, the use of this technique is feasible in a conventional X-ray laboratory and does not require access to a synchrotron radiation source.