Thorium (Th) and lanthanide elements, owing to their highly similar ionic radii and coordination environments, have long posed significant challenges in rare-earth mineral separation and nuclear fuel cycle processes. In recent years, selective crystallization separation has emerged as an important research direction, offering a green and efficient strategy to address this issue. This paper, grounded in the pedagogical needs of crystallography and coordination chemistry, explores how the mechanisms, experimental methodologies, and application cases of Th/lanthanide elements separation can be integrated into postgraduate courses in inorganic and coordination chemistry, drawing upon the latest advances in research. Through case-driven teaching and the development of experimental platforms, students are not only able to appreciate the value of crystallization separation in resource recovery and nuclear energy utilisation, but also gain a systematic understanding of interdisciplinary core principles such as molecular recognition, lattice differentiation amplification, and structural modulation. In research practice, three metal-organic complexes, namely Gd (BDA)(NO₃)(H₂O)₃, Ln₂(BDA)₃(H₂O)₃·H₂O, and Th(BDA)₂(H₂O)₂·H₂O (abbreviated as Ln-1, Ln-2, and Th-1, respectively), were successfully synthesised under hydrothermal conditions using 2,2′-bipyridine-6,6′-dicarboxylic acid (H₂BDA) as the ligand, thereby revealing the crystallization patterns of lanthanide elements under identical reaction conditions. Further binary and multicomponent Th/Ln crystallization separation experiments demonstrated that Th-1 preferentially precipitates, achieving efficient one-step separation of Th⁴⁺, with separation factors as high as 920.2 in Th/Ln (Ln=Gd, Tb, Dy, Ho) systems. This study illustrates that the deep integration of cutting-edge scientific problems into teaching not only provides an intuitive demonstration of the scientific principles and application prospects of crystallization separation, but also fosters postgraduate students' innovative research capabilities and interdisciplinary competence in tackling complex chemical challenges.
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