Syntheses, crystal structures, and vibrational spectroscopic properties of MgCN2, SrCN2, and BaCN2

Article abstract of DOI:10.1016/0925-8388(94)90032-9

The alkaline-earth metal cyanamides MgCN₂, SrCN₂, and BaCN₂ were prepared by the reaction of melamine with the metal nitrides (Mg₃N₂, Sr₂N, Ba₃N₂) at temperatures between 740 °C and 850 °C. MgCN₂ was structurally characterized by X-ray analysis using powder methods (R3m, Z = 3, a = 327.34(1) pm, c = 1412.82(5) pm). The crystal structures of SrCN₂ and BaCN₂ were determined from X-ray single crystal data (SrCN₂: Pnma, Z = 4, a = 1241.0(2) pm, b = 396.3(2) pm, c = 538.9(2) pm, BaCN₂: R3c, Z = 18, a = 1528.2(2) pm, c = 701.3(2) pm). All compounds consist of the respective cations and CN₂^2--anions with an increasing degree of distortion of the coordination polyhedra with increasing radii of the cations. The structural features are correlated with vibrational spectroscopic data.