DOE OSTI2020
Na5(HgSn5)2 is Magnesium tetraboride-derived structured and crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. there are three inequivalent Na sites. In the first Na site, Na is bonded in a 2-coordinate geometry to two equivalent Hg and eight Sn atoms. Both Na–Hg bond lengths are 3.25 Å. There are a spread of Na–Sn bond distances ranging from 3.62–3.71 Å. In the second Na site, Na is bonded in a 7-coordinate geometry to one Hg and seven Sn atoms. The Na–Hg bond length is 3.25 Å. There are a spread of Na–Sn bond distances ranging from 3.26–3.73 Å. In the third Na site, Na is bonded in a 8-coordinate geometry to two equivalent Hg and six Sn atoms. There are one shorter (3.27 Å) and one longer (3.42 Å) Na–Hg bond lengths. There are a spread of Na–Sn bond distances ranging from 3.25–3.58 Å. Hg is bonded in a 8-coordinate geometry to four Na and four Sn atoms. There are a spread of Hg–Sn bond distances ranging from 2.91–3.13 Å. There are five inequivalent Sn sites. In the first Sn site, Sn is bonded in a 8-coordinate geometry to four Na, one Hg, and three Sn atoms. There are two shorter (2.93 Å) and one longer (3.06 Å) Sn–Sn bond lengths. In the second Sn site, Sn is bonded in a 7-coordinate geometry to three Na, one Hg, and three Sn atoms. There are one shorter (2.95 Å) and one longer (2.98 Å) Sn–Sn bond lengths. In the third Sn site, Sn is bonded in a 7-coordinate geometry to three Na and four Sn atoms. There are a spread of Sn–Sn bond distances ranging from 2.94–3.14 Å. In the fourth Sn site, Sn is bonded in a 7-coordinate geometry to three Na, one Hg, and three Sn atoms. The Sn–Sn bond length is 2.97 Å. In the fifth Sn site, Sn is bonded in a 8-coordinate geometry to four Na, one Hg, and three Sn atoms.