Abstract In the history of discovery of elements, praseodymium and neodymium were found to be unique and accompanied by each other. In 1839, Swedish scientist Mosander obtained “didymium” in ceria, and predicted the existence of new elements, but did not isolate corresponding elements. In 1882, Brauner used a spectroscope to test the absorption bands belonging to praseodymium and neodymium respectively. In 1885, the Austrian chemist Karl Orls Wellsbach using the method of double nitrate and ammonium fractionation crystallization, from the “didymium” to separate the praseodymium and neodymium elemental, confirmed the existence of new elements hypothesis, praseodymium and neodymium elements basic formation of the concept. From 1972 to 1976, Chinese chemist Xu Guangxian put forward the Theory of Countercurrent Extraction, which made outstanding contribution to the improvement of the purity of praseodymium and neodymium after separation. In the 20th century, with the rise of isotope chemistry, the isotopes of praseodymium and neodymium were discovered successively, forming the modern concept of praseodymium and neodymium. In short, the discovery of praseodymium and neodymium and the development of their concepts are the crystallization of the integration of scientific thought and technology.
SHANG Xiao-Shuo, YUAN Zhen-Dong, LI Meng. Discovery of “Twin Elements” Praseodymium and Neodymium and the Development of Their Concepts[J]. Chinese Journal of Chemical Education, 2024, 45(22): 123-129.
