Zur Kenntnis der Selenidosilikate und -germanate Na4Si4Se10, Na2GeSe3 und Na8Ge4Se10 / On the Selenidosilicates and Germanates Na4Si4Se10, Na2GeSe3 and Na8Ge4Se10

Abstract

The following new compounds have been prepared and structurally characterized: Na4Si4Se10: orthorhombic, space group Cmcm (No. 63). a = 1340.9(5) pm, b = 1318.4(5) pm, c = 1086.5(4) pm, Z = 4. ρx = 3.44 g/cm3, ρexp = 3.47 g/cm3. The compound crystallizes in the Na4Si4S10 type with adamantane analogous Si4Se10 4- anions. Na2GeSe3: Monoclinic, space group P21/c (No. 14). a = 709.7(2) pm, b = 1606.8(5) pm, c = 607.3(2) pm, β = 113.69(8)°, Z = 4, ρx = 3.72 g/cm3, ρexp = 3.76 g/cm3. The compound is isotypic with Na2GeS3. GeSe4-tetrahedra are connected by common corners to infinite “Zweiereinfach” chains. Na8Ge4Se10: monoclinic, space group P21/c (No. 14). a = 1310.4(5) pm, b = 1205.7(5) pm, c = 1410.1(5) pm, β = 92.9(1)°, Z = 4, ρx = 3.77 g/cm3, ρexp = 3.75 g/cm3. Analogous to Na8Ge4Te10 (mod. I), two octahedral Ge2Se6 - units are connected by a common edge to a Ge4Se10 8-“ - anion.