DOE OSTI2020
Ba20Hg99Cd4 crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are four inequivalent Ba sites. In the first Ba site, Ba is bonded in a 6-coordinate geometry to eighteen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.76–3.85 Å. In the second Ba site, Ba is bonded in a 11-coordinate geometry to seventeen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.54–4.07 Å. In the third Ba site, Ba is bonded in a 1-coordinate geometry to fifteen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.43–3.70 Å. In the fourth Ba site, Ba is bonded in a 12-coordinate geometry to sixteen Hg atoms. There are a spread of Ba–Hg bond distances ranging from 3.76–3.97 Å. There are twelve inequivalent Hg sites. In the first Hg site, Hg is bonded in a 7-coordinate geometry to four Ba and four Hg atoms. There are a spread of Hg–Hg bond distances ranging from 2.97–3.09 Å. In the second Hg site, Hg is bonded to three equivalent Ba and nine Hg atoms to form distorted face-sharing HgBa3Hg9 cuboctahedra. There are a spread of Hg–Hg bond distances ranging from 3.18–3.33 Å. In the third Hg site, Hg is bonded in a tetrahedral geometry to four equivalent Ba atoms. In the fourth Hg site, Hg is bonded in a distorted body-centered cubic geometry to four Ba, three Hg, and one Cd atom. The Hg–Hg bond length is 3.02 Å. The Hg–Cd bond length is 3.23 Å. In the fifth Hg site, Hg is bonded in a distorted q6 geometry to three equivalent Ba and six Hg atoms. There are three shorter (3.15 Å) and three longer (3.20 Å) Hg–Hg bond lengths. In the sixth Hg site, Hg is bonded in a 7-coordinate geometry to three equivalent Ba, three equivalent Hg, and one Cd atom. All Hg–Hg bond lengths are 3.10 Å. The Hg–Cd bond length is 3.14 Å. In the seventh Hg site, Hg is bonded in a 10-coordinate geometry to four Ba and six Hg atoms. In the eighth Hg site, Hg is bonded in a 10-coordinate geometry to two Ba and eight Hg atoms. There are two shorter (3.18 Å) and two longer (3.36 Å) Hg–Hg bond lengths. In the ninth Hg site, Hg is bonded in a 1-coordinate geometry to three Ba, three Hg, and one Cd atom. The Hg–Cd bond length is 2.93 Å. In the tenth Hg site, Hg is bonded in a distorted trigonal planar geometry to three Ba atoms. In the eleventh Hg site, Hg is bonded in a 8-coordinate geometry to three Ba and five Hg atoms. There are one shorter (2.98 Å) and two longer (3.04 Å) Hg–Hg bond lengths. In the twelfth Hg site, Hg is bonded in a 1-coordinate geometry to three equivalent Ba, three equivalent Hg, and one Cd atom. The Hg–Cd bond length is 3.25 Å. Cd is bonded in a body-centered cubic geometry to eight Hg atoms.