Na₂₉Zn₂₄Sn₃₂: A zintl phase containing a novel type of {Sn₁₄} enneahedra and heteroatomic {Zn ₈Sn₄} icosahedra

(Figure Presented) A new type of polyhedron: An {Sn₁₄} enneahedron, which can be derived from a trigonal bipyramid by truncating the three equatorial vertices, occurs in linear chains in Na₂₉Zn ₂₄Sn₃₂ (see picture; Sn blue). A pseudorotation of the {Sn₁₄} enneahedron allows the number of covalent interactions within the complex three-dimensional atom arrangement to be adjusted, so that an electron-precise Zintl phase is attained.