Materials Data on CdHg6(As2Br3)2 by Materials Project

Abstract

Hg6Cd(As2Br3)2 crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. Hg2+ is bonded to two As2- and four equivalent Br1- atoms to form distorted HgAs2Br4 octahedra that share corners with eight equivalent HgAs2Br4 octahedra, corners with two AsHg3As tetrahedra, edges with two equivalent CdBr6 octahedra, and edges with four equivalent HgAs2Br4 octahedra. The corner-sharing octahedra tilt angles range from 14–88°. There are one shorter (2.60 Å) and one longer (2.61 Å) Hg–As bond lengths. There are a spread of Hg–Br bond distances ranging from 3.11–3.36 Å. Cd2+ is bonded to six equivalent Br1- atoms to form CdBr6 octahedra that share edges with twelve equivalent HgAs2Br4 octahedra. All Cd–Br bond lengths are 2.84 Å. There are two inequivalent As2- sites. In the first As2- site, As2- is bonded to three equivalent Hg2+ and one As2- atom to form AsHg3As tetrahedra that share corners with three equivalent HgAs2Br4 octahedra, corners with six equivalent BrCdHg4 square pyramids, corners with three equivalent AsHg3As tetrahedra, and edges with three equivalent BrCdHg4 square pyramids. The corner-sharing octahedral tilt angles are 70°. The As–As bond length is 2.46 Å. In the second As2- site, As2- is bonded to three equivalent Hg2+ and one As2- atom to form AsHg3As tetrahedra that share corners with three equivalent HgAs2Br4 octahedra, corners with six equivalent BrCdHg4 square pyramids, corners with three equivalent AsHg3As tetrahedra, and edges with three equivalent BrCdHg4 square pyramids. The corner-sharing octahedral tilt angles are 73°. Br1- is bonded to four equivalent Hg2+ and one Cd2+ atom to form distorted BrCdHg4 square pyramids that share corners with nine equivalent BrCdHg4 square pyramids, corners with four AsHg3As tetrahedra, edges with four equivalent BrCdHg4 square pyramids, and edges with two AsHg3As tetrahedra.