Between Elemental Match and Mismatch: From K(12)Ge(3.5)Sb(6) to Salts of (Ge(2)Sb(2))(2−), (Ge(4)Sb(12))(4−), and (Ge(4)Sb(14))(4−)

The solid mixture “K(2)GeSb” was shown to comprise single‐crystalline K(12)Ge(3.5)Sb(6) (1), a double salt of K(5)[GeSb(3)] with carbonate‐like [GeSb(3)](5−) anions, and the metallic Zintl phase K(2)Ge(1.5). Extraction of 1 with ethane‐1,2‐diamine in the presence of crypt‐222 afforded [K(crypt‐222)](+) salts of several novel binary Zintl anions: (Ge(2)Sb(2))(2−) (in 2), (Ge(4)Sb(12))(4−) (in 3), and in the presence of [AuMePPh(3)] also (Ge(4)Sb(14))(4−) (in 4). The anion in 2 represents a predicted, yet heretofore missing pseudo‐tetrahedral anion. 4 comprises a cluster analogous to (Ge(4)Bi(14))(4−) and (Ga(2)Bi(16))(4−), and thus one of the most Sb‐rich binary p‐block anions. The unprecedented cluster topology in 3 can be viewed as a defect‐version of the one in 4 upon following a “dead end” of cluster growth. The findings indicate that Ge and Sb atoms are at the border of a well‐matching and a mismatch elemental combination. We discuss the syntheses, the geometric structures, and the electronic structures of the new compounds.