Crystal Structures of and Displacive Transitions in OsN2, IrN2, RuN2, and RhN2

摘要

Solid nitrides are attracting increasing interest due to their importance in both fundamental science and technological applications.[1]-[5] Recently, the nitrides of Os, Ir, and Pt were synthesized under extreme conditions.[6]-[14] These discoveries are quite surprising since the noble transition metals (Os, Ir, Pt, Ru, Rh, Pd) were for many years thought not to form nitrides.[15], [16] This emerging field has attracted much interest,[6]-[14], [17] and these compounds have been shown to have very intriguing properties, such as an ultra-high bulk modulus (428 GPa for IrN2).[11] To date, however, only the crystal structure of PtN2 has been solved;[10], [12]-[14] the crystal structures of IrN2 and OsN2 are still an open question. Because the crystal structure is an important prerequisite for understanding the properties of crystalline solids,[18] the lack of such information has hindered the development of this new field.