Über das Oxoindat Ba4In2O7

On the Oxoindate Ba₄In₂O₇ Ba₄In₂O₇ was prepared for the first time by solid state reaction and investigated by X-ray methods. (Space group D_4h¹⁷–14/mmm, a = 4.175; c = 29.483 Å; Z = 2). It shows a close crystal chemical relationship to Ba₃In₂O₆ and La₂SrCu₂O₆. One of the oxygen point positions is occupied only by a half. This fact alleviates the understanding of the layer structure of Ba₄In₂O₇. The compound is compared with Sr₄Tl₂O₇ and a further discussion in respect to Ba₅In₂O₈ shows the probable identity of Ba₅In₂O₈ with Ba₄In₂O₇.