Synthesis, Structure, and Disorder in Na₃₆Sn₅<i>Pn</i>₁₈ (<i>Pn</i> = P, Sb)

Solid ion conducting materials are important components for all‐solid‐state batteries. Recently, solid lithium‐ion‐conducting materials with tetrahedral E P 4 units are discovered for E = Si, Ge, Sn, Al, Ga, and In. The increasing demand for high‐performance and low‐cost battery technology promotes the search for new sodium‐ion‐conducting materials, since sodium holds promise to be a cheap and abundant alternative for lithium. In this work, the synthesis and characterization of the two new compounds Na 36 Sn 5 Pn 18 ( Pn = P, Sb) are reported. Both phases are obtained via ball‐milling procedures and subsequent annealing processes. Crystallographic investigations based on single‐crystal X‐ray diffraction data reveal that both compounds crystallize in the space group I 4 1 / amd (no. 141). The structure can be described based on a distorted cubic closed packing of Pn atoms with Sn atoms located in tetrahedral voids. Additionally, a dimeric ethane analogue Sn 2 Pn 6 unit is present that can be understood as a Sn 2 dumbbell that occupies an octahedral void. In the P derivative, an additional disorder is observed which reveals trigonal planar SnP 3 beside SnP 4 and Sn 2 P 6 units. Both compounds correspond to electron‐precise Zintl phases.