Materials Data on Sm2Sn5 by Materials Project

Sm2Sn5 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent Sm sites. In the first Sm site, Sm is bonded to twelve Sn atoms to form a mixture of corner and face-sharing SmSn12 cuboctahedra. There are a spread of Sm–Sn bond distances ranging from 3.28–3.40 Å. In the second Sm site, Sm is bonded in a 10-coordinate geometry to ten Sn atoms. There are a spread of Sm–Sn bond distances ranging from 3.25–3.56 Å. There are six inequivalent Sn sites. In the first Sn site, Sn is bonded in a distorted rectangular see-saw-like geometry to four Sm and six Sn atoms. There are four shorter (3.28 Å) and two longer (3.31 Å) Sn–Sn bond lengths. In the second Sn site, Sn is bonded in a 8-coordinate geometry to six equivalent Sm and two equivalent Sn atoms. Both Sn–Sn bond lengths are 3.09 Å. In the third Sn site, Sn is bonded in a distorted square co-planar geometry to four equivalent Sm atoms. In the fourth Sn site, Sn is bonded in a distorted rectangular see-saw-like geometry to four equivalent Sm and four Sn atoms. Both Sn–Sn bond lengths are 3.32 Å. In the fifth Sn site, Sn is bonded in a 4-coordinate geometry to four Sm and six Sn atoms. In the sixth Sn site, Sn is bonded in a distorted square co-planar geometry to four equivalent Sm atoms.

Sm₂Sn₅ 结晶于正交晶系（orthorhombic）的Cmmm空间群，其结构为三维框架。体系中存在两类不等价的钐（Sm）原子位点：在第一类钐位点中，钐原子与十二个锡原子成键，形成兼具共角与共面连接的SmSn₁₂立方八面体（cuboctahedra）结构单元，钐-锡键长分布范围为3.28~3.40 Å。在第二类钐位点中，钐原子采取10配位几何构型，与十个锡原子成键，对应的钐-锡键长分布范围为3.25~3.56 Å。体系中存在六类不等价的锡（Sn）原子位点：在第一类锡位点中，锡原子采取畸变矩形跷跷板状几何构型，与四个钐原子及六个锡原子配位，包含四个键长为3.28 Å的较短锡-锡键与两个键长为3.31 Å的较长锡-锡键。在第二类锡位点中，锡原子采取8配位几何构型，与六个等价的钐原子及两个等价的锡原子成键，两处锡-锡键长均为3.09 Å。在第三类锡位点中，锡原子采取畸变正方形共面几何构型，仅与四个等价的钐原子配位。在第四类锡位点中，锡原子采取畸变矩形跷跷板状几何构型，与四个等价的钐原子及四个锡原子配位，两处锡-锡键长均为3.32 Å。在第五类锡位点中，锡原子采取4配位几何构型，与四个钐原子及六个锡原子配位。在第六类锡位点中，锡原子采取畸变正方形共面几何构型，仅与四个等价的钐原子配位。