Materials Data on U8FeSe17 by Materials Project

U8FeSe17 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent U+3.88+ sites. In the first U+3.88+ site, U+3.88+ 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 U+3.88+ site, U+3.88+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.86–2.94 Å. In the third U+3.88+ site, U+3.88+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.80–3.11 Å. Fe3+ is bonded in an octahedral geometry to six Se2- atoms. There are two shorter (2.41 Å) and four longer (2.56 Å) Fe–Se bond lengths. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four U+3.88+ atoms to form distorted SeU4 trigonal pyramids that share corners with two equivalent SeU6 octahedra, corners with six equivalent SeU3Fe tetrahedra, edges with two equivalent SeU3Fe tetrahedra, and an edgeedge with one SeU4 trigonal pyramid. The corner-sharing octahedral tilt angles are 38°. In the second Se2- site, Se2- is bonded to six U+3.88+ atoms to form SeU6 octahedra that share corners with four equivalent SeU3Fe 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 U+3.88+ atoms. In the fourth Se2- site, Se2- is bonded to three U+3.88+ and one Fe3+ atom to form distorted SeU3Fe tetrahedra that share a cornercorner with one SeU6 octahedra, corners with five equivalent SeU3Fe tetrahedra, corners with three equivalent SeU4 trigonal pyramids, edges with two equivalent SeU3Fe tetrahedra, and an edgeedge with one SeU4 trigonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the fifth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four U+3.88+ atoms. In the sixth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three U+3.88+ and one Fe3+ atom. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.88+ atoms.

八硒化铁铀（U₈FeSe₁₇）以单斜晶系C2/m空间群结晶。该晶体为三维结构，存在三个不等价的U⁺3.88+位点。在第一个U⁺3.88+位点中，U⁺3.88+以八配位几何构型与8个Se²⁻原子成键，U–Se键长分布范围为2.86~3.02 Å。在第二个U⁺3.88+位点中，U⁺3.88+以八配位几何构型与8个Se²⁻原子成键，U–Se键长分布范围为2.86~2.94 Å。在第三个U⁺3.88+位点中，U⁺3.88+以八配位几何构型与8个Se²⁻原子成键，U–Se键长分布范围为2.80~3.11 Å。Fe³+以八面体几何构型与6个Se²⁻原子成键，存在2条较短的Fe–Se键（键长2.41 Å）与4条较长的Fe–Se键（键长2.56 Å）。存在七个不等价的Se²⁻位点：在第一个Se²⁻位点中，Se²⁻与4个U⁺3.88+原子成键，形成畸变的SeU₄三角锥构型，该三角锥与2个等价的SeU₆八面体共享顶点、与6个等价的SeU₃Fe四面体共享顶点、与2个等价的SeU₃Fe四面体共享边，并与1个SeU₄三角锥共享边，共顶点八面体的倾斜角为38°。在第二个Se²⁻位点中，Se²⁻与6个U⁺3.88+原子成键，形成SeU₆八面体构型，该八面体与4个等价的SeU₃Fe四面体共享顶点，并与4个等价的SeU₄三角锥共享顶点。在第三个Se²⁻位点中，Se²⁻以矩形跷跷板状几何构型与4个U⁺3.88+原子成键。在第四个Se²⁻位点中，Se²⁻与3个U⁺3.88+原子和1个Fe³+原子成键，形成畸变的SeU₃Fe四面体构型，该四面体与1个SeU₆八面体共享顶点、与5个等价的SeU₃Fe四面体共享顶点、与3个等价的SeU₄三角锥共享顶点、与2个等价的SeU₃Fe四面体共享边，并与1个SeU₄三角锥共享边，共顶点八面体的倾斜角为53°。在第五个Se²⁻位点中，Se²⁻以矩形跷跷板状几何构型与4个U⁺3.88+原子成键。在第六个Se²⁻位点中，Se²⁻以畸变矩形跷跷板状几何构型与3个U⁺3.88+原子和1个Fe³+原子成键。在第七个Se²⁻位点中，Se²⁻以畸变矩形跷跷板状几何构型与4个U⁺3.88+原子成键。