From Oxides to Nitrides: Recent Developments in the Structural Chemistry of Alkali/Alkaline Earth Metal Sub‐Compounds

[N 6 CaBa 14 ] clusters separated by a matrix of sodium atoms that can alternatively be considered as stars of octahedra (shown on the right) comprising face‐shared [NCaBa 5 ] octahedra with common Ca vertices are present in Na 14 Ba 14 CaN 6 recently described by Simon and Steinbrenner ( Angew. Chem. Int. Ed. Engl. 1996 , 35 , 552). This compound, the first discrete subnitride cluster, is not only a link between Na/Ba subnitrides and the classic Rb/Cs suboxides, but also an important extension of the structural chemistry of this class of compounds—not least because a “real” cation (Ca 2+ ) is present in the saltlike interior of the cluster.