Determination and application of the reaction between REOCl (RE = Y, Gd and Sm) and H 2 O

The reaction between rare earth oxychloride (REOCl) and water was investigated. X-ray diffractometer, volumetric titrations, FTIR spectrograph and scanning electron microscope were used to determine the reaction process and the reaction products. It was found that the reaction could be concluded as follows: 5REOCl(s) + 5H 2 O(l) = 2RE 2 (OH) 5 Cl(s) + RE 3+ (aq) + 3Cl − (aq). Based on this reaction, a new method for determining the purity of anhydrous rare earth chloride was proposed. Compared with the conventional method, the maximum absolute error decreased from 22 to < 1% and the maximum relative error decreased from 111 to < 4% under the experimental conditions. Graphic abstract