Materials Data on U8CoSe17 by Materials Project

U8CoSe17 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent U4+ sites. In the first U4+ site, U4+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.86–3.02 Å. In the second U4+ site, U4+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.85–2.90 Å. In the third U4+ site, U4+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.81–3.06 Å. Co2+ is bonded in an octahedral geometry to six Se2- atoms. There are two shorter (2.35 Å) and four longer (2.50 Å) Co–Se bond lengths. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four U4+ atoms to form distorted SeU4 trigonal pyramids that share corners with two equivalent SeU6 octahedra, corners with six equivalent SeU3Co tetrahedra, edges with two equivalent SeU3Co tetrahedra, and an edgeedge with one SeU4 trigonal pyramid. The corner-sharing octahedral tilt angles are 39°. In the second Se2- site, Se2- is bonded to six U4+ atoms to form SeU6 octahedra that share corners with four equivalent SeU3Co tetrahedra and corners with four equivalent SeU4 trigonal pyramids. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four U4+ atoms. In the fourth Se2- site, Se2- is bonded to three U4+ and one Co2+ atom to form distorted SeU3Co tetrahedra that share a cornercorner with one SeU6 octahedra, corners with five equivalent SeU3Co tetrahedra, corners with three equivalent SeU4 trigonal pyramids, edges with two equivalent SeU3Co tetrahedra, and an edgeedge with one SeU4 trigonal pyramid. The corner-sharing octahedral tilt angles are 54°. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three U4+ and one Co2+ atom. In the sixth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four U4+ atoms. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U4+ atoms.

U8CoSe17 结晶于单斜晶系C2/m空间群，其晶体结构为三维框架。体系中存在3个不等价的四价铀（U⁴⁺）位点：在第一个U⁴⁺位点中，U⁴⁺采取八配位几何构型，与8个二价硒（Se²⁻）离子配位，U–Se键长分布范围为2.86~3.02 Å；在第二个U⁴⁺位点中，U⁴⁺同样以八配位几何与8个Se²⁻离子配位，U–Se键长范围为2.85~2.90 Å；在第三个U⁴⁺位点中，U⁴⁺仍为八配位，与8个Se²⁻离子结合，U–Se键长分布为2.81~3.06 Å。二价钴（Co²⁺）采取八面体配位几何，与6个Se²⁻离子配位，其Co–Se键长包含2个较短的（2.35 Å）与4个较长的（2.50 Å）两类。
体系中共存在7个不等价的Se²⁻位点：
1. 第一个Se²⁻位点中，Se²⁻与4个U⁴⁺离子结合，形成畸变的SeU₄三角锥结构，该结构分别与2个等价的SeU₆八面体共享顶角、与6个等价的SeU₃Co四面体共享顶角、与2个等价的SeU₃Co四面体共享边，还与1个SeU₄三角锥共享一条边；其共顶角八面体倾斜角为39°。
2. 第二个Se²⁻位点中，Se²⁻与6个U⁴⁺离子配位，形成SeU₆八面体结构，该八面体分别与4个等价的SeU₃Co四面体、4个等价的SeU₄三角锥共享顶角。
3. 第三个Se²⁻位点中，Se²⁻采取类矩形跷板式配位几何，与4个U⁴⁺离子结合。
4. 第四个Se²⁻位点中，Se²⁻与3个U⁴⁺和1个Co²⁺离子配位，形成畸变的SeU₃Co四面体结构，该四面体与1个SeU₆八面体共享一个顶角、与5个等价的SeU₃Co四面体共享顶角、与3个等价的SeU₄三角锥共享顶角、与2个等价的SeU₃Co四面体共享边，还与1个SeU₄三角锥共享一条边；其共顶角八面体倾斜角为54°。
5. 第五个Se²⁻位点中，Se²⁻采取畸变类矩形跷板式配位几何，与3个U⁴⁺和1个Co²⁺离子结合。
6. 第六个Se²⁻位点中，Se²⁻采取类矩形跷板式配位几何，与4个U⁴⁺离子配位。
7. 第七个Se²⁻位点中，Se²⁻采取畸变类矩形跷板式配位几何，与4个U⁴⁺离子结合。