DOI: 10.17188/1688231
title: Materials Data on Tb2MgS4 by Materials Project

description: MgTb2S4 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share corners with three equivalent TbS6 octahedra, corners with four equivalent TbS7 pentagonal bipyramids, edges with two equivalent MgS6 octahedra, edges with three equivalent TbS6 octahedra, and edges with three equivalent TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 10–53°. There are a spread of Mg–S bond distances ranging from 2.54–2.66 Å. There are two inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to seven S2- atoms to form distorted TbS7 pentagonal bipyramids that share corners with four equivalent MgS6 octahedra, corners with four equivalent TbS6 octahedra, edges with three equivalent MgS6 octahedra, edges with three equivalent TbS6 octahedra, and faces with two equivalent TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 17–67°. There are a spread of Tb–S bond distances ranging from 2.73–3.07 Å. In the second Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share corners with three equivalent MgS6 octahedra, corners with four equivalent TbS7 pentagonal bipyramids, edges with two equivalent TbS6 octahedra, edges with three equivalent MgS6 octahedra, and edges with three equivalent TbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 10–53°. There are a spread of Tb–S bond distances ranging from 2.71–2.78 Å. There are four inequivalent S2- sites. In the first 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 five equivalent STb3Mg tetrahedra, edges with four STb3Mg2 square pyramids, an edgeedge with one STb3Mg tetrahedra, and edges with two equivalent STb4Mg trigonal bipyramids. In the second S2- site, S2- is bonded to two equivalent Mg2+ and three Tb3+ atoms to form STb3Mg2 square pyramids that share corners with two equivalent STb3Mg2 square pyramids, corners with two equivalent STb3Mg tetrahedra, corners with six equivalent STb4Mg trigonal bipyramids, edges with five STb3Mg2 square pyramids, edges with two equivalent STb3Mg tetrahedra, and an edgeedge with one STb4Mg trigonal bipyramid. In the third S2- site, S2- is bonded to two equivalent Mg2+ and three Tb3+ atoms to form STb3Mg2 square pyramids that share corners with two equivalent STb3Mg2 square pyramids, corners with five equivalent STb3Mg tetrahedra, corners with two equivalent STb4Mg trigonal bipyramids, edges with five STb3Mg2 square pyramids, an edgeedge with one STb3Mg tetrahedra, and edges with three equivalent STb4Mg trigonal bipyramids. In the fourth S2- site, S2- is bonded to one Mg2+ and three Tb3+ atoms to form distorted STb3Mg tetrahedra that share corners with seven STb3Mg2 square pyramids, corners with two equivalent STb3Mg tetrahedra, corners with five equivalent STb4Mg trigonal bipyramids, edges with three STb3Mg2 square pyramids, and an edgeedge with one STb4Mg trigonal bipyramid.