Na10SrSn12 crystallizes in the cubic I-43m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to four equivalent Sn(1) atoms to form corner-sharing NaSn4 tetrahedra. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to nine equivalent Sn(1) atoms. Sr(1) is bonded in a 12-coordinate geometry to twelve equivalent Sn(1) atoms. Sn(1) is bonded in a 9-coordinate geometry to two equivalent Na(1), three equivalent Na(2), one Sr(1), and three equivalent Sn(1) atoms.
Na10SrSn12 crystallizes in the cubic I-43m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to four equivalent Sn(1) atoms to form corner-sharing NaSn4 tetrahedra. All Na(1)-Sn(1) bond lengths are 3.22 Å. In the second Na site, Na(2) is bonded in a 9-coordinate geometry to nine equivalent Sn(1) atoms. There are three shorter (3.43 Å) and six longer (3.55 Å) Na(2)-Sn(1) bond lengths. Sr(1) is bonded in a 12-coordinate geometry to twelve equivalent Sn(1) atoms. All Sr(1)-Sn(1) bond lengths are 3.47 Å. Sn(1) is bonded in a 9-coordinate geometry to two equivalent Na(1), three equivalent Na(2), one Sr(1), and three equivalent Sn(1) atoms. There is one shorter (2.92 Å) and two longer (3.00 Å) Sn(1)-Sn(1) bond lengths.