Nitrido-Silicate. I. Hochtemperatur-Synthese und Kristallstruktur von Ca2Si5N8

Nitrido Silicates. I. High Temperature Synthesis and Crystal Structure of Ca₂Si₅N₈ Ca₂Si₅N₈ is obtained by reaction of silicon diimide with metallic calcium under nitrogen atmosphere performed in a specially developed high-frequency furnace at temperatures between 1 500 and 1 600°C. Ca₂Si₅N₈ (Cc, a = 1 435.2(3), b = 561.0(1), c = 968.9(2) pm, β = 112.06(3)°, Z = 4, R = 0.023, wR = 0.018) contains Ca²⁺ ions as well as a three-dimensional covalent network structure of corner-sharing SiN₄ tetrahedra. Two sorts of N occur with molar ratio 1:1 which are bonded to two and three Si, respectively.