Materials Data on Tb2MgS4 by Materials Project

MgTb2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share corners with six TbS6 octahedra and edges with three TbS6 octahedra. The corner-sharing octahedra tilt angles range from 59–66°. There are a spread of Mg–S bond distances ranging from 2.40–2.48 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 four equivalent TbS6 octahedra, corners with two equivalent MgS4 tetrahedra, edges with four TbS6 octahedra, and edges with two equivalent MgS4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Tb–S bond distances ranging from 2.72–2.79 Å. In the second Tb3+ site, Tb3+ is bonded to six S2- atoms to form TbS6 octahedra that share corners with eight TbS6 octahedra, corners with four equivalent MgS4 tetrahedra, edges with two equivalent TbS6 octahedra, and an edgeedge with one MgS4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–55°. There are a spread of Tb–S bond distances ranging from 2.74–2.83 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Tb3+ atoms. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Tb3+ atoms. In the third S2- site, S2- is bonded to one Mg2+ and three Tb3+ atoms to form distorted corner-sharing STb3Mg trigonal pyramids.

MgTb₂S₄ 具有类尖晶石结构（Spinel-like structured），结晶于正交晶系Pnma空间群（orthorhombic Pnma space group）。该结构为三维空间骨架。Mg²+（Mg2+）与四个S²-（S2-）原子配位，形成MgS₄四面体（MgS4 tetrahedra），该四面体与六个TbS₆八面体（TbS6 octahedra）共顶点，同时与三个TbS₆八面体共边。共顶点八面体的倾斜角范围为59°~66°。Mg-S键的键长分布区间为2.40~2.48 Å。体系中存在两个非等价的Tb³+（Tb3+）位点：在第一个Tb³+位点中，Tb³+与六个S²-原子配位形成TbS₆八面体，该八面体与四个等价的TbS₆八面体共顶点、与两个等价的MgS₄四面体共顶点，同时与四个TbS₆八面体共边、与两个等价的MgS₄四面体共边；此类共顶点八面体的倾斜角范围为51°~55°，Tb-S键的键长分布区间为2.72~2.79 Å。在第二个Tb³+位点中，Tb³+与六个S²-原子配位形成TbS₆八面体，该八面体与八个TbS₆八面体共顶点、与四个等价的MgS₄四面体共顶点，同时与两个等价的TbS₆八面体共边、与一个MgS₄四面体共边；此类共顶点八面体的倾斜角范围为46°~55°，Tb-S键的键长分布区间为2.74~2.83 Å。体系中存在三个非等价的S²-位点：在第一个S²-位点中，S²-以矩形跷跷板型几何构型与一个Mg²+和三个Tb³+原子配位；在第二个S²-位点中，S²-同样以矩形跷跷板型几何构型与一个Mg²+和三个Tb³+原子配位；在第三个S²-位点中，S²-与一个Mg²+和三个Tb³+原子配位，形成发生畸变的共顶点STb₃Mg三角锥（trigonal pyramids）。