Materials Data on Tb2MgS4 by Materials Project

MgTb2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to five S2- atoms to form MgS5 square pyramids that share corners with four TbS6 octahedra, edges with four TbS6 octahedra, and edges with four equivalent MgS5 square pyramids. The corner-sharing octahedra tilt angles range from 4–5°. There are a spread of Mg–S bond distances ranging from 2.54–2.65 Å. There are two inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share corners with three equivalent TbS6 octahedra, corners with two equivalent MgS5 square pyramids, edges with six TbS6 octahedra, and an edgeedge with one MgS5 square pyramid. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Tb–S bond distances ranging from 2.70–2.84 Å. In the second Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share corners with three equivalent TbS6 octahedra, corners with two equivalent MgS5 square pyramids, edges with four TbS6 octahedra, and edges with three equivalent MgS5 square pyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Tb–S bond distances ranging from 2.65–2.85 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Mg2+ and two equivalent Tb3+ atoms to form a mixture of edge and corner-sharing STb2Mg3 square pyramids. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Tb3+ atoms. In the third S2- site, S2- is bonded in a 3-coordinate geometry to three Tb3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Mg2+ and three Tb3+ atoms to form STb3Mg2 square pyramids that share corners with two equivalent STb2Mg3 square pyramids and edges with five STb3Mg2 square pyramids.