Characterization of Radium Sulphate

[摘要] This paper examines the crystal structure of radium sulphate and compares its structure to barium sulphate, strontium sulphate, and lead sulphate. The radium sulphate powder was measured by bothpowder X-ray diffraction and EXAFS. The unit cell was determined to be orthorhombic, belonging to thePnma(no. 62) space group with the cell parametersa=9.07 Å,b=5.52 Å,c=7.28 Å, andV=364.48 Å3. These data support the fact that radium sulphate is isostructural with barium, strontium, and lead sulphate. The bond distances were determined using EXAFS. The mean Ra–O and S–O bond distances were found to be 2.96(2) Å and 1.485(8) Å, respectively, and the Ra–O–S bond angle was127(2)∘. Findings of EXAFS data are quite consistent and support the XRD data.These findings show that it is possible for radium to coprecipitate with barium, strontium, and lead in sulphate media to form a substitutional solid solution.

[学科分类] 无机化学