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

The new carbodiimide compounds LaF(CN2) and LiPr2F3(CN2)2 were obtained as crystalline powders by solid‐state metathesis reactions from 1:1 molar ratios of REF3 (RE = rare earth) and Li2(CN2) at temperatures between 500 and 700 °C over 4 days in fused copper ampoules. Higher proportions of Li2(CN2) in reactions yielded RE2(CN2)3 compounds, including the new Eu2(CN2)3. Single‐crystal structure refinements were performed for LaF(CN2) and LiPr2F3(CN2)2. Homologous LiRE2F3(CN2)2 compounds with RE = Ce, Pr, Nd, Sm, Eu, Gd were assigned by isotypic indexing of their XRD patterns. The crystal structure of LaF(CN2) contains planar [La3F3] layers being interconnected by carbodiimide ions, and is related with that of the mineral bastnäsite (REF(CO3)).