Evaluation on the crystal structure of ningyoite using XRD analysis

Suzuki, Chikashi ; Nakagiri, Toshio  

The environmental researches in Ningyo-toge area about disposal of uranium waste require estimation of long-term migration behaviors of uranium compounds buried for disposal. For this purpose, formation mechanism and stability of uranium minerals in Ningyo-toge area such as ningyoite are important. However, the crystal structure of ningyoite are unclear, though the X-ray diffraction (XRD) pattern of ningyoite were observed and included in International Centre for Diffraction Data (ICDD). We investigated the XRD pattern of ningyoite using XRD analysis code. This investigation showed that peak positions of the XRD pattern by our present analysis are close to those of the ICDD data, though some peak intensities are different. Detailed analysis shows the peaks of the intensities remarkably different from those of the ICDD data which were formed by superimpose of multiple peaks.