DOI: 10.17188/1708794
title: Materials Data on Tb2MgS4 by Materials Project

description: MgTb2S4 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one MgTb2S4 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent TbS6 octahedra, and corners with six TbS4 tetrahedra. The corner-sharing octahedra tilt angles range from 60–62°. There are a spread of Mg–S bond distances ranging from 2.44–2.48 Å. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share a cornercorner with one MgS4 tetrahedra, corners with five TbS4 tetrahedra, edges with two equivalent MgS6 octahedra, and edges with four equivalent TbS6 octahedra. There are a spread of Mg–S bond distances ranging from 2.69–2.75 Å. There are four inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to four S2- atoms to form TbS4 tetrahedra that share a cornercorner with one TbS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four TbS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–63°. There are a spread of Tb–S bond distances ranging from 2.59–2.62 Å. In the second Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share corners with two equivalent MgS4 tetrahedra, corners with four TbS4 tetrahedra, edges with two equivalent TbS6 octahedra, and edges with four equivalent MgS6 octahedra. There are a spread of Tb–S bond distances ranging from 2.76–2.85 Å. In the third Tb3+ site, Tb3+ is bonded to four S2- atoms to form TbS4 tetrahedra that share a cornercorner with one TbS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four TbS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–65°. There are a spread of Tb–S bond distances ranging from 2.58–2.61 Å. In the fourth Tb3+ site, Tb3+ is bonded to four S2- atoms to form TbS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent TbS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four TbS4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–64°. There are a spread of Tb–S bond distances ranging from 2.59–2.61 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Mg2+ and two Tb3+ atoms to form a mixture of distorted edge and corner-sharing STb2Mg2 tetrahedra. In the second S2- site, S2- is bonded to two Mg2+ and two equivalent Tb3+ atoms to form distorted STb2Mg2 tetrahedra that share corners with nine STb2Mg2 tetrahedra and edges with three STb3Mg tetrahedra. In the third S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Tb3+ atoms. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three Tb3+ atoms. In the fifth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Tb3+ atoms. In the sixth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two Tb3+ atoms. In the seventh S2- site, S2- is bonded to one Mg2+ and three Tb3+ atoms to form distorted STb3Mg tetrahedra that share corners with nine STb2Mg2 tetrahedra and edges with three STb3Mg tetrahedra. In the eighth S2- site, S2- is bonded to two equivalent Mg2+ and two Tb3+ atoms to form distorted STb2Mg2 tetrahedra that share corners with nine STb2Mg2 tetrahedra and edges with three STb3Mg tetrahedra.