Sr3[Al2N4]: Ein Nitridoaluminat mit gewellten Tetraederketten 1 ∞[AlN4/2 3–] / Sr3[Al2N4]: A Nitridoaluminate with Corrugated Tetrahedral Chains 1 ∞[AlN4/2 3-]

Abstract

Sr3[Al2N4] (Pnna, Nr. 52; a = 590.1(3), b = 1000.5(5), c = 958.0(4) pm; Z = 4) was prepared from the elements (molar ratio Sr: Al = 3:1; reaction with N2, 1 atm, 24 h; Tmax = 1100 °C). The crystal structure contains corrugated chains 1 ∞ [AlN4/2 3-] which consist of distorted AlN4 tetrahedra sharing common edges (Al-N : 188.5(7)-195.8(7) pm; N-Al-N : 95.0(3)- 126.0(5)°). The nitrogen atom s form a distorted ccp arrangement. 3/4 of the octahedral holes are occupied by Sr atoms; 1/4 of the tetrahedral holes are occupied by Al atoms. Sr3[Al2N4] can be described in terms of the Zintl concept (isosteric relation of [AIN2]3- to SiS2).