Materials Data on SnHg6(As2Br3)2 by Materials Project
Hg6Sn(As2Br3)2 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to two As+2.50- and four Br1- atoms to form HgAs2Br4 octahedra that share corners with eight HgAs2Br4 octahedra, corners with two AsHg3As tetrahedra, and edges with four equivalent HgAs2Br4 octahedra. The corner-sharing octahedra tilt angles range from 11–84°. Both Hg–As bond lengths are 2.60 Å. There are a spread of Hg–Br bond distances ranging from 3.08–3.52 Å. In the second Hg2+ site, Hg2+ is bonded to two As+2.50- and four Br1- atoms to form distorted HgAs2Br4 octahedra that share corners with eight HgAs2Br4 octahedra, corners with two AsHg3As tetrahedra, and edges with four equivalent HgAs2Br4 octahedra. The corner-sharing octahedra tilt angles range from 11–84°. Both Hg–As bond lengths are 2.61 Å. There are a spread of Hg–Br bond distances ranging from 2.98–3.53 Å. Sn4+ is bonded in a 6-coordinate geometry to six Br1- atoms. There are three shorter (2.82 Å) and three longer (3.35 Å) Sn–Br bond lengths. There are four inequivalent As+2.50- sites. In the first As+2.50- site, As+2.50- is bonded to three equivalent Hg2+ and one As+2.50- atom to form AsHg3As tetrahedra that share corners with three equivalent HgAs2Br4 octahedra and corners with three equivalent AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 68°. The As–As bond length is 2.46 Å. In the second As+2.50- site, As+2.50- is bonded to three equivalent Hg2+ and one As+2.50- atom to form AsHg3As tetrahedra that share corners with three equivalent HgAs2Br4 octahedra and corners with three equivalent AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 71°. In the third As+2.50- site, As+2.50- is bonded to three equivalent Hg2+ and one As+2.50- atom to form AsHg3As tetrahedra that share corners with three equivalent HgAs2Br4 octahedra and corners with three equivalent AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 71°. The As–As bond length is 2.46 Å. In the fourth As+2.50- site, As+2.50- is bonded to three equivalent Hg2+ and one As+2.50- atom to form AsHg3As tetrahedra that share corners with three equivalent HgAs2Br4 octahedra and corners with three equivalent AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 73°. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 5-coordinate geometry to four Hg2+ and one Sn4+ atom. In the second Br1- site, Br1- is bonded in a 5-coordinate geometry to four Hg2+ and one Sn4+ atom.