Materials Data on Sm4CrS7 by Materials Project

Sm4CrS7 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a distorted rectangular see-saw-like geometry to four S2- atoms. There are one shorter (2.63 Å) and three longer (2.65 Å) Sm–S bond lengths. In the second Sm3+ site, Sm3+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Sm–S bond distances ranging from 2.70–3.12 Å. Cr2+ is bonded to six equivalent S2- atoms to form face-sharing CrS6 octahedra. There are three shorter (2.55 Å) and three longer (2.64 Å) Cr–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to four Sm3+ atoms. In the second S2- site, S2- is bonded to four Sm3+ atoms to form corner-sharing SSm4 tetrahedra. In the third S2- site, S2- is bonded to three equivalent Sm3+ and two equivalent Cr2+ atoms to form distorted SSm3Cr2 square pyramids that share corners with two equivalent SSm3Cr2 square pyramids, corners with three equivalent SSm4 tetrahedra, edges with four equivalent SSm3Cr2 square pyramids, and faces with two equivalent SSm3Cr2 square pyramids.

Sm₄CrS₇ 结晶于六方晶系P6₃空间群，其晶体结构为三维骨架结构。体系中存在两个不等价的三价钐（Sm³⁺）离子配位位点：在第一个配位位点中，Sm³⁺以畸变矩形跷跷板型配位模式与四个二价硫（S²⁻）离子成键，Sm-S键长分为两组，包含1个短键（2.63 Å）与3个长键（2.65 Å）；在第二个配位位点中，Sm³⁺以七配位模式与七个S²⁻离子成键，该位点的Sm-S键距分布范围为2.70~3.12 Å。二价铬（Cr²⁺）与六个等价的S²⁻离子配位，形成面共享型CrS₆八面体结构基元，Cr-S键长同样分为两组，包含3个短键（2.55 Å）与3个长键（2.64 Å）。体系中存在三个不等价的S²⁻离子配位位点：在第一个硫离子配位位点中，S²⁻以畸变矩形跷跷板型配位模式与四个Sm³⁺离子成键；在第二个硫离子配位位点中，S²⁻与四个Sm³⁺离子配位，形成角共享型SSm₄四面体结构基元；在第三个硫离子配位位点中，S²⁻与三个等价的Sm³⁺离子及两个等价的Cr²⁺离子配位，形成畸变SSm₃Cr₂四方锥结构基元，该四方锥分别与两个等价的SSm₃Cr₂四方锥共享顶点、与三个等价的SSm₄四面体共享顶点、与四个等价的SSm₃Cr₂四方锥共享边，同时与两个等价的SSm₃Cr₂四方锥共享面。