The Versatility of Solid‐State Metathesis Reactions: From Rare Earth Fluorides to Carbodiimides

The new carbodiimide compounds LaF(CN 2 ) and LiPr 2 F 3 (CN 2 ) 2 were obtained as crystalline powders by solid‐state metathesis reactions from 1:1 molar ratios of RE F 3 ( RE = rare earth) and Li 2 (CN 2 ) at temperatures between 500 and 700 °C over 4 days in fused copper ampoules. Higher proportions of Li 2 (CN 2 ) in reactions yielded RE 2 (CN 2 ) 3 compounds, including the new Eu 2 (CN 2 ) 3 . Single‐crystal structure refinements were performed for LaF(CN 2 ) and LiPr 2 F 3 (CN 2 ) 2 . Homologous Li RE 2 F 3 (CN 2 ) 2 compounds with RE = Ce, Pr, Nd, Sm, Eu, Gd were assigned by isotypic indexing of their XRD patterns. The crystal structure of LaF(CN 2 ) contains planar [La 3 F 3 ] layers being interconnected by carbodiimide ions, and is related with that of the mineral bastnäsite ( RE F(CO 3 )).