Abstract
We present the first nitridic analogs of micas, namely AESi(3) P(4) N(10) (NH)(2) (AE=Mg, Mg(0.94) Ca(0.06) , Ca, Sr), which were synthesized under high-pressure high-temperature conditions at 1400 °C and 8 GPa from the refractory nitrides P(3) N(5) and Si(3) N(4) , the respective alkaline earth amides, implementing NH(4) F as a mineralizer. The crystal structure was elucidated by single-crystal diffraction with microfocused synchrotron radiation, energy-dispersive X-ray spectroscopic (EDX) mapping with atomic resolution, powder X-ray diffraction, and solid-state NMR. The structures consist of typical tetrahedra-octahedra-tetrahedra (T-O-T) layers with P occupying T and Si occupying O layers, realizing the rare motif of sixfold coordinated silicon atoms in nitrides. The presence of H, as an imide group forming the SiN(4) (NH)(2) octahedra, is confirmed by SCXRD, MAS-NMR, and IR spectroscopy. Eu(2+) -doped samples show tunable narrow-band emission from deep blue to cyan (451-492 nm).