Materials Data on K2Hg3Se4 by Materials Project
K2Hg3Se4 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. K1+ is bonded to six Se2- atoms to form KSe6 octahedra that share corners with four equivalent HgSe4 tetrahedra, edges with six equivalent KSe6 octahedra, and an edgeedge with one HgSe4 tetrahedra. There are a spread of K–Se bond distances ranging from 3.42–3.51 Å. There are two inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to four Se2- atoms to form HgSe4 tetrahedra that share corners with eight equivalent KSe6 octahedra and edges with two equivalent KSe6 octahedra. The corner-sharing octahedra tilt angles range from 28–86°. There are two shorter (2.74 Å) and two longer (2.76 Å) Hg–Se bond lengths. In the second Hg2+ site, Hg2+ is bonded in a distorted rectangular see-saw-like geometry to four Se2- atoms. There are a spread of Hg–Se bond distances ranging from 2.54–3.31 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent K1+ and three Hg2+ atoms. In the second Se2- site, Se2- is bonded to three equivalent K1+ and three Hg2+ atoms to form a mixture of distorted edge and corner-sharing SeK3Hg3 octahedra. The corner-sharing octahedra tilt angles range from 5–69°.