Solid‐State Synthesis of LaCl ₃ and NdCl ₃ via Ammonium Chloride Chlorination: Optimization Through Full Factorial Design

Abstract Lanthanum(III) chloride (LaCl 3 ) and neodymium(III) chloride (NdCl 3 ) were synthesized by solid‐state chlorination of La 2 O 3 and Nd 2 O 3 using NH 4 Cl as a chlorinating agent under an inert atmosphere. A 2 3 full factorial design was employed to evaluate the effects of temperature, contact time, and stoichiometry on reaction yield. First‐order models were developed to describe the dependence of yield on the synthesis parameters, revealing statistically significant positive main effects and notable two‐factor interactions. Optimal conditions for LaCl 3 (95.18% yield) were determined as 325 °C, 120 min, and La 2 O 3 :NH 4 Cl molar ratio of 1:24. For NdCl 3 , the maximum yield (93.65%) was achieved under identical temperature and stoichiometry, with a reduced contact time of 90 min. These results highlight the effectiveness of factorial experimental design in optimizing lanthanide halide syntheses via dry chlorination.