Über Oxidpnictide: Zur Kenntnis von A₂Mn₃B₂O₂ mit A = Sr, Ba und B = As, Sb, Bi / On Oxidpnictides: Preparation and Crystal Structure of A₂Mn₃B₂O₂ with A = Sr, Ba and B = As, Sb, Bi

Abstract

Five new oxidpnictides have been prepared and structurally characterized. They crystallize in the tetragonal system, I4/mmm, with the following constants: Sr 2 Mn 3 As 2 O 2 : a = 416 ± 1 pm, c = 1884 ± 4 pm, c/a = 4.529, Ba 2 Mn 3 As 2 O 2 : a = 424.8 ± 0 5 pm, c = 1977 ± 3 pm, c/a = 4.654, Sr 2 Mn 3 Sb 2 O 2 : a = 426.2 ± 0.4 pm, c = 2011 ± 2 pm, c/a = 4.718, Ba 2 Mn 3 Sb 2 O 2 : a = 436.7 ± 0.5 pm, c = 2078 ± 2 pm, c/a = 4.758, Sr 2 Mn 3 Bi 2 O 2 : a = 428 ± 1 pm, c = 2055 ± 5 pm, c/a = 4.801. Mn- and As(Sb,Bi) atoms form tetragonal pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Sr atoms, in which Mn and O atoms are located forming MnO 4 square plane nets.