Materials Data on CuHgSeBr by Materials Project
CuHgSeBr crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. Cu1+ is bonded to two equivalent Se2- and two Br1- atoms to form CuSe2Br2 tetrahedra that share corners with two equivalent HgSe2Br4 octahedra, corners with two equivalent CuSe2Br2 tetrahedra, edges with two equivalent HgSe2Br4 octahedra, and an edgeedge with one CuSe2Br2 tetrahedra. The corner-sharing octahedral tilt angles are 53°. Both Cu–Se bond lengths are 2.41 Å. There are one shorter (2.47 Å) and one longer (2.63 Å) Cu–Br bond lengths. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded in a rectangular see-saw-like geometry to two equivalent Se2- and two equivalent Br1- atoms. Both Hg–Se bond lengths are 2.57 Å. Both Hg–Br bond lengths are 3.14 Å. In the second Hg2+ site, Hg2+ is bonded to two equivalent Se2- and four equivalent Br1- atoms to form distorted HgSe2Br4 octahedra that share corners with four equivalent HgSe2Br4 octahedra, corners with four equivalent CuSe2Br2 tetrahedra, edges with four equivalent HgSe2Br4 octahedra, and edges with four equivalent CuSe2Br2 tetrahedra. The corner-sharing octahedral tilt angles are 22°. Both Hg–Se bond lengths are 2.55 Å. All Hg–Br bond lengths are 3.43 Å. Se2- is bonded to two equivalent Cu1+ and two Hg2+ atoms to form corner-sharing SeCu2Hg2 trigonal pyramids. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 4-coordinate geometry to two equivalent Cu1+ and two equivalent Hg2+ atoms. In the second Br1- site, Br1- is bonded in a 6-coordinate geometry to two equivalent Cu1+ and four equivalent Hg2+ atoms.