Zwei neue Erdalkalimetall-Oxoindate: BaCa2In6O12 und BaSr2In6O12

Two New Alkaline-Earth-Oxoindates: BaCa₂In₆O₁₂ and BaSr₂In₆O₁₂ The hitherto unknown compounds (I): BaCa₂In₆O₁₂ and (II): BaSr₂In₆O₁₂ were prepared and examined by single crystal X-Ray work. (I) and (II) crystallize with hexagonal symmetry, space group C? P6₃/m, with (I): a = 9.880, c = 3.211 Å; (II): a = 9.9443; c = 3.2671 Å, Z = 1. Both compounds are isotypic to the metastable oxide AM₂Ln₆O₁₂, but without metastable behavior. The [In₆O₁₂]^6? network is occupied by the alkaline earth ions. One of the tunnels is stuffed by Ca²⁺ and Sr²⁺ respectively, the other one by Ba²⁺ in a statistical distribution on possible point positions. (I) and (II) prove the existence of the AM₂Ln₆O₁₂-type in respect to small Ln³⁺ ions.