DOI: 10.17188/1714903
title: Materials Data on Tb2MgS4 by Materials Project

description: MgTb2S4 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share a cornercorner with one TbS6 octahedra, corners with two equivalent MgS6 octahedra, corners with four TbS7 pentagonal bipyramids, an edgeedge with one MgS6 octahedra, edges with four TbS6 octahedra, and edges with three TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 12–54°. There are a spread of Mg–S bond distances ranging from 2.54–2.82 Å. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share a cornercorner with one TbS6 octahedra, corners with two equivalent MgS6 octahedra, corners with four TbS7 pentagonal bipyramids, an edgeedge with one MgS6 octahedra, edges with four TbS6 octahedra, and edges with three TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 12–54°. There are a spread of Mg–S bond distances ranging from 2.55–2.74 Å. There are four inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent TbS6 octahedra, corners with four TbS7 pentagonal bipyramids, an edgeedge with one TbS6 octahedra, edges with four MgS6 octahedra, and edges with three TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 12–54°. There are a spread of Tb–S bond distances ranging from 2.70–2.77 Å. In the second Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent TbS6 octahedra, corners with four TbS7 pentagonal bipyramids, an edgeedge with one TbS6 octahedra, edges with four MgS6 octahedra, and edges with three TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 12–54°. There are a spread of Tb–S bond distances ranging from 2.68–2.79 Å. In the third Tb3+ site, Tb3+ is bonded to seven S2- atoms to form distorted TbS7 pentagonal bipyramids that share corners with four MgS6 octahedra, corners with four TbS6 octahedra, edges with three MgS6 octahedra, edges with three TbS6 octahedra, and faces with two equivalent TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 16–69°. There are a spread of Tb–S bond distances ranging from 2.73–3.03 Å. In the fourth Tb3+ site, Tb3+ is bonded to seven S2- atoms to form distorted TbS7 pentagonal bipyramids that share corners with four MgS6 octahedra, corners with four TbS6 octahedra, edges with three MgS6 octahedra, edges with three TbS6 octahedra, and faces with two equivalent TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 17–68°. There are a spread of Tb–S bond distances ranging from 2.73–3.03 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to two Mg2+ and three Tb3+ atoms to form distorted STb3Mg2 trigonal bipyramids that share corners with two equivalent STb3Mg2 square pyramids, corners with three equivalent STb3Mg tetrahedra, corners with two equivalent STb3Mg2 trigonal bipyramids, edges with five STb3Mg2 square pyramids, and edges with three STb3Mg2 trigonal bipyramids. In the second S2- site, S2- is bonded to two Mg2+ and three Tb3+ atoms to form distorted STb3Mg2 trigonal bipyramids that share corners with six STb3Mg2 square pyramids, corners with two equivalent STb3Mg tetrahedra, corners with two equivalent STb3Mg2 trigonal bipyramids, edges with three STb3Mg2 square pyramids, an edgeedge with one STb3Mg tetrahedra, and edges with three STb3Mg2 trigonal bipyramids. In the third S2- site, S2- is bonded to one Mg2+ and three Tb3+ atoms to form a mixture of distorted edge and corner-sharing STb3Mg tetrahedra. In the fourth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Tb3+ atoms. In the fifth S2- site, S2- is bonded to two Mg2+ and three Tb3+ atoms to form distorted STb3Mg2 square pyramids that share a cornercorner with one STb3Mg tetrahedra, corners with eight STb3Mg2 trigonal bipyramids, edges with four STb3Mg2 square pyramids, an edgeedge with one STb3Mg tetrahedra, and edges with two STb3Mg2 trigonal bipyramids. In the sixth S2- site, S2- is bonded to two Mg2+ and three Tb3+ atoms to form distorted STb3Mg2 square pyramids that share corners with two equivalent STb4Mg square pyramids, a cornercorner with one STb3Mg tetrahedra, corners with six STb3Mg2 trigonal bipyramids, edges with three STb3Mg2 square pyramids, an edgeedge with one STb3Mg tetrahedra, and edges with three STb3Mg2 trigonal bipyramids. In the seventh S2- site, S2- is bonded to one Mg2+ and four Tb3+ atoms to form distorted STb4Mg square pyramids that share corners with two equivalent STb3Mg2 square pyramids, corners with two equivalent STb3Mg tetrahedra, corners with two equivalent STb4Mg trigonal bipyramids, edges with three STb3Mg2 square pyramids, an edgeedge with one STb3Mg tetrahedra, and edges with five STb3Mg2 trigonal bipyramids. In the eighth S2- site, S2- is bonded to one Mg2+ and four Tb3+ atoms to form distorted STb4Mg trigonal bipyramids that share corners with eight STb3Mg2 square pyramids, corners with three equivalent STb3Mg tetrahedra, edges with two STb3Mg2 square pyramids, and edges with four STb3Mg2 trigonal bipyramids.