Abstract:
The continuation of the synthesis of new rare-earth carbodiimide compounds was performed with the preparative tool of solid-state metathesis (SSM) reactions by combining rare-earth fluorides with carbodiimide sources like Li2CN2, Na2CN2, or SrCN2. This research of SSM has been performed for various molar ratios of reaction partners. The homologous series rare-earth carbodiimides having the formula RE2(CN2)3 has been added by the new Eu2(CN2)3, and the dimorphic character of Tm2(CN2)3 has been explored. The new mixed-valent europium fluoride carbodiimide compound Eu4F5(CN2)2 was prepared and its crystal structure was refined by X-ray single-crystal diffraction. The ratio of Eu3+- and Eu2+-ions in the structure of Eu4F5(CN2)2 was confirmed by Mößbauer spectroscopy and by magnetic measurements.
New compounds having the composition of LiRE(CN2)2 (RE = La, Ce, Pr) were synthesized by solid-state metathesis reactions and their structures were refined by single-crystal diffraction.
The thermal conversion of LiRE(CN2)2 (RE = La, Ce) has lead to the first rare-earth carbodiimide nitrides having the composition RE3(CN2)2N. The structure was refined by single-crystal X-ray diffraction in space group P212121.
A novel family of carbodiimide compounds was discovered from SSM reactions containing homoleptic and heteroleptic cyanamidoaluminate ions. The first example of a homoleptic tetracyanamidoaluminate having the composition LiM2[Al(CN2)4] (M = Sr, Eu) was characterized by X-ray single-crystal diffraction. The first example of a heteroleptic cyanamidoaluminate having the composition Eu3[AlF2(CN2)3(CN)] was synthesized and characterized by X-ray single-crystal diffraction, Raman-, and IR-spectroscopy.