The Intermetallic Type-I Clathrate Na8Zn4Ge42

The new intermetallic type-I clathrate Na₈Zn₄Ge₄₂ was obtained by direct reaction of the elements, and its crystal structure was determined by means of single-crystal X-ray diffraction methods. The structure is described in space group Pm3 n (no. 223) with a = 10.6982(1) Å. A mixed Zn/Ge occupancy is found for one of the network sites (6c). Na₈Zn₄Ge₄₂ represents an air-stable electron-precise Zintl phase with exclusively Na cations located in the cavities of a polyanionic host network of four-connected Zn and Ge atoms.