Materials Data on Er2HfS5 by Materials Project

Er2HfS5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Er–S bond distances ranging from 2.80–2.95 Å. Hf4+ is bonded to seven S2- atoms to form distorted edge-sharing HfS7 pentagonal bipyramids. There are a spread of Hf–S bond distances ranging from 2.51–2.68 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Er3+ and two equivalent Hf4+ atoms to form distorted SEr2Hf2 tetrahedra that share corners with four equivalent SEr4Hf square pyramids, corners with six equivalent SEr2Hf2 tetrahedra, corners with four SEr4Hf trigonal bipyramids, an edgeedge with one SEr4Hf square pyramid, an edgeedge with one SEr2Hf2 tetrahedra, and edges with four SEr4Hf trigonal bipyramids. In the second S2- site, S2- is bonded to four equivalent Er3+ and one Hf4+ atom to form distorted SEr4Hf trigonal bipyramids that share corners with five equivalent SEr4Hf square pyramids, corners with four equivalent SEr2Hf2 tetrahedra, corners with five SEr4Hf trigonal bipyramids, edges with two equivalent SEr4Hf square pyramids, edges with four equivalent SEr2Hf2 tetrahedra, and edges with four equivalent SEr4Hf trigonal bipyramids. In the third S2- site, S2- is bonded to four equivalent Er3+ and one Hf4+ atom to form SEr4Hf square pyramids that share corners with eight equivalent SEr2Hf2 tetrahedra, corners with nine SEr4Hf trigonal bipyramids, edges with two equivalent SEr4Hf square pyramids, edges with two equivalent SEr2Hf2 tetrahedra, edges with three SEr4Hf trigonal bipyramids, and a faceface with one SEr4Hf trigonal bipyramid. In the fourth S2- site, S2- is bonded to four equivalent Er3+ and one Hf4+ atom to form distorted SEr4Hf trigonal bipyramids that share corners with four equivalent SEr4Hf square pyramids, corners with four equivalent SEr2Hf2 tetrahedra, corners with five SEr4Hf trigonal bipyramids, an edgeedge with one SEr4Hf square pyramid, edges with four equivalent SEr2Hf2 tetrahedra, edges with four equivalent SEr4Hf trigonal bipyramids, and a faceface with one SEr4Hf square pyramid.