Site‐Specific Substitution Preferences in the Solid Solutions Li₁₂Si7–xGex, Li12–yNaySi₇, Na₇LiSi8–zGez, and Li₃NaSi6–vGev

The mixed silicide‐germanides Li 12 Si 7– x Ge x , Na 7 LiSi 8– z Ge z , and Li 3 NaSi 6– v Ge v which could serve as potential precursors for Si 1– x Ge x materials were synthesized and characterized by X‐ray diffraction methods. The full solid solution series Li 12 Si 7– x Ge x (0 ≤ x ≤ 7) is easily accessible from the elements and features preferential occupation of the more negatively charged crystallographic tetrel positions by Ge, which is the more electronegative element. In case of Na 7 LiSi 8– z Ge z a broad solid solution range of 1.3 ≤ x ≤ 8 is available but the ternary silicide Na 7 LiSi 8 could not be obtained by the tested methods of synthesis. The solubility of Ge in Li 3 NaSi 6– v Ge v is highly limited to a maximum of v ≈ 0.5, and again the formally more negatively charged tetrel positions are preferred by Ge. Additionally, the two crystallographic Li positions in Li 12 Si 7 with unusually large displacement parameters can be partially substituted by Na in Li 12– y Na y Si 7 with 0 ≤ y ≤ 0.6. The statistical mixing of Li and Na in this solid solution contrasts the typical ordering of Li and Na in most ternary tetrelides.