Materials Data on K2HgCl4 by Materials Project

Abstract

K2HgCl4 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to seven Cl1- atoms to form distorted KCl7 pentagonal bipyramids that share corners with two equivalent HgCl6 octahedra, corners with six KCl7 pentagonal bipyramids, edges with four equivalent HgCl6 octahedra, edges with three KCl7 pentagonal bipyramids, and faces with two equivalent KCl7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of K–Cl bond distances ranging from 3.18–3.32 Å. In the second K1+ site, K1+ is bonded to seven Cl1- atoms to form distorted KCl7 pentagonal bipyramids that share corners with two equivalent HgCl6 octahedra, corners with six KCl7 pentagonal bipyramids, edges with four equivalent HgCl6 octahedra, edges with three KCl7 pentagonal bipyramids, and faces with two equivalent KCl7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of K–Cl bond distances ranging from 3.17–3.31 Å. Hg2+ is bonded to six Cl1- atoms to form HgCl6 octahedra that share corners with four KCl7 pentagonal bipyramids, edges with two equivalent HgCl6 octahedra, and edges with eight KCl7 pentagonal bipyramids. There are two shorter (2.48 Å) and four longer (2.97 Å) Hg–Cl bond lengths. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded to three equivalent K1+ and two equivalent Hg2+ atoms to form ClK3Hg2 trigonal bipyramids that share corners with twelve ClK3Hg2 trigonal bipyramids and edges with eight ClK4Hg trigonal bipyramids. In the second Cl1- site, Cl1- is bonded to three equivalent K1+ and two equivalent Hg2+ atoms to form a mixture of edge and corner-sharing ClK3Hg2 trigonal bipyramids. In the third Cl1- site, Cl1- is bonded to four K1+ and one Hg2+ atom to form a mixture of distorted edge and corner-sharing ClK4Hg trigonal bipyramids.