DOE OSTI2020
K18Na46Tl31 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are four inequivalent K sites. In the first K site, K is bonded in a 4-coordinate geometry to four K, eight Na, and four Tl atoms. There are two shorter (4.50 Å) and two longer (4.51 Å) K–K bond lengths. There are a spread of K–Na bond distances ranging from 4.03–4.15 Å. There are two shorter (4.02 Å) and two longer (4.03 Å) K–Tl bond lengths. In the second K site, K is bonded in a 4-coordinate geometry to four K, eight Na, and four Tl atoms. Both K–K bond lengths are 4.52 Å. There are a spread of K–Na bond distances ranging from 4.02–4.14 Å. There are a spread of K–Tl bond distances ranging from 4.02–4.06 Å. In the third K site, K is bonded in a 4-coordinate geometry to two equivalent K, ten Na, and four Tl atoms. Both K–K bond lengths are 4.27 Å. There are four shorter (4.12 Å) and six longer (4.17 Å) K–Na bond lengths. There are two shorter (4.02 Å) and two longer (4.08 Å) K–Tl bond lengths. In the fourth K site, K is bonded in a 5-coordinate geometry to two equivalent K, ten Na, and five Tl atoms. Both K–K bond lengths are 4.26 Å. There are a spread of K–Na bond distances ranging from 4.12–4.17 Å. There are a spread of K–Tl bond distances ranging from 4.03–4.12 Å. There are nine inequivalent Na sites. In the first Na site, Na is bonded in a 4-coordinate geometry to four K and four Tl atoms. There are a spread of Na–Tl bond distances ranging from 3.23–3.31 Å. In the second Na site, Na is bonded in a 4-coordinate geometry to four K and four Tl atoms. There are a spread of Na–Tl bond distances ranging from 3.23–3.30 Å. In the third Na site, Na is bonded in a 1-coordinate geometry to three equivalent K and four Tl atoms. There are one shorter (3.31 Å) and three longer (3.44 Å) Na–Tl bond lengths. In the fourth Na site, Na is bonded in a 1-coordinate geometry to three equivalent K and four Tl atoms. There are one shorter (3.31 Å) and three longer (3.47 Å) Na–Tl bond lengths. In the fifth Na site, Na is bonded in a 5-coordinate geometry to three K and five Tl atoms. There are a spread of Na–Tl bond distances ranging from 3.34–3.63 Å. In the sixth Na site, Na is bonded in a 1-coordinate geometry to three K and four Tl atoms. There are a spread of Na–Tl bond distances ranging from 3.31–3.63 Å. In the seventh Na site, Na is bonded in a 12-coordinate geometry to four K and four Tl atoms. There are two shorter (3.30 Å) and two longer (3.32 Å) Na–Tl bond lengths. In the eighth Na site, Na is bonded in a 1-coordinate geometry to three K and four Tl atoms. There are a spread of Na–Tl bond distances ranging from 3.34–3.49 Å. In the ninth Na site, Na is bonded in a 1-coordinate geometry to three K and four Tl atoms. There are one shorter (3.35 Å) and three longer (3.47 Å) Na–Tl bond lengths. There are eleven inequivalent Tl sites. In the first Tl site, Tl is bonded to three equivalent K, six Na, and three equivalent Tl atoms to form distorted face-sharing TlK3Na6Tl3 cuboctahedra. All Tl–Tl bond lengths are 3.34 Å. In the second Tl site, Tl is bonded to three equivalent K, six Na, and three equivalent Tl atoms to form distorted face-sharing TlK3Na6Tl3 cuboctahedra. All Tl–Tl bond lengths are 3.35 Å. In the third Tl site, Tl is bonded in a 12-coordinate geometry to two equivalent K, six Na, and four Tl atoms. There are two shorter (3.33 Å) and two longer (3.36 Å) Tl–Tl bond lengths. In the fourth Tl site, Tl is bonded in a 12-coordinate geometry to two equivalent K, six Na, and four Tl atoms. There are two shorter (3.33 Å) and two longer (3.34 Å) Tl–Tl bond lengths. In the fifth Tl site, Tl is bonded in a 12-coordinate geometry to three K, six Na, and three Tl atoms. Both Tl–Tl bond lengths are 3.37 Å. In the sixth Tl site, Tl is bonded in a 12-coordinate geometry to three K, six Na, and three Tl atoms. Both Tl–Tl bond lengths are 3.38 Å. In the seventh Tl site, Tl is bonded in a 12-coordinate geometry to three equivalent K, six Na, and three equivalent Tl atoms. In the eighth Tl site, Tl is bonded in a 12-coordinate geometry to three equivalent K, six Na, and three equivalent Tl atoms. In the ninth Tl site, Tl is bonded in a distorted body-centered cubic geometry to seven Na and one Tl atom. The Tl–Tl bond length is 3.12 Å. In the tenth Tl site, Tl is bonded in a 7-coordinate geometry to seven Na atoms. In the eleventh Tl site, Tl is bonded in a 11-coordinate geometry to three equivalent K, six equivalent Na, and two equivalent Tl atoms.