<i>Ln</i>₃[SiON₃]O (<i>Ln</i> = La, Ce, Pr) – Three Oxonitridosilicate Oxides with Crystal Structures Derived from the Anti‐Perovskite Structure Type

Abstract

Abstract The oxonitridosilicate oxides Ln 3 [SiON 3 ]O with Ln = La, Ce, Pr were obtained by high‐temperature syntheses (1450–1600 °C) in a radio‐frequency furnace. The crystal structures were determined from single‐crystal X‐ray diffraction data and confirmed by Rietveld refinements. The compounds Ln 3 [SiON 3 ]O crystallize in space group I 4/ mcm (La 3 [SiON 3 ]O: a = 6.8224(10), c = 11.074(2) Å, Z = 4; R 1 = 0.0240; Ce 3 [SiON 3 ]O: a = 6.7233(10), c = 11.069(2) Å, Z = 4, R 1 = 0.0234; Pr 3 [SiON 3 ]O: a = 6.6979(9), c = 11.005(2) Å, Z = 4; R 1 = 0.0156) and they were found to be isotypic with Gd 3 [SiON 3 ]O, whose structure derives from the anti ‐perovskite structure type. In the crystal structure there are elongated O Ln 6 ‐octahedra, which are interconnected through common vertices. In the cavities of this network there are exclusively non‐condensed SiON 3 tetrahedra. 29 Si solid‐state NMR investigations, lattice energy calculations (MAPLE) and EDX measurements confirmed the crystal structure and the chemical compositions. For Ce 3 [SiON 3 ]O, magnetic susceptibility measurements were carried out and the paramagnetic behavior with an experimental magnetic moment of 2.2 μ B per cerium atom indicates Ce 3+ .