Materials Data on Eu2Al6Si3Au2 by Materials Project

Eu2Au2Al6Si3 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. there are two inequivalent Eu sites. In the first Eu site, Eu is bonded in a 8-coordinate geometry to four equivalent Au, eight Al, and four equivalent Si atoms. All Eu–Au bond lengths are 3.35 Å. There are four shorter (3.40 Å) and four longer (3.43 Å) Eu–Al bond lengths. All Eu–Si bond lengths are 3.37 Å. In the second Eu site, Eu is bonded in a 12-coordinate geometry to eight Al and eight Si atoms. There are four shorter (3.29 Å) and four longer (3.44 Å) Eu–Al bond lengths. There are four shorter (3.31 Å) and four longer (3.38 Å) Eu–Si bond lengths. There are two inequivalent Au sites. In the first Au site, Au is bonded in a body-centered cubic geometry to eight Al atoms. There are four shorter (2.61 Å) and four longer (2.66 Å) Au–Al bond lengths. In the second Au site, Au is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Al, and one Si atom. All Au–Al bond lengths are 2.59 Å. The Au–Si bond length is 2.51 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to two equivalent Eu and four Au atoms to form a mixture of distorted face, edge, and corner-sharing AlEu2Au4 tetrahedra. In the second Al site, Al is bonded to two equivalent Eu, two equivalent Au, and two equivalent Si atoms to form distorted AlEu2Si2Au2 tetrahedra that share corners with fourteen AlEu2Au4 tetrahedra, edges with four AlEu2Au4 tetrahedra, and faces with four equivalent AlEu2Si2Au2 tetrahedra. Both Al–Si bond lengths are 2.58 Å. In the third Al site, Al is bonded to four Eu and four Si atoms to form distorted AlEu4Si4 tetrahedra that share corners with twelve AlEu2Au4 tetrahedra, edges with six AlEu2Au4 tetrahedra, and faces with four equivalent AlEu4Si4 tetrahedra. All Al–Si bond lengths are 2.58 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Al, and one Si atom. The Si–Si bond length is 2.42 Å. In the second Si site, Si is bonded in a 1-coordinate geometry to four equivalent Eu, one Au, and four equivalent Al atoms. In the third Si site, Si is bonded in a 9-coordinate geometry to four equivalent Eu, four equivalent Al, and one Si atom.

Eu₂Au₂Al₆Si₃晶体结晶于四方晶系I4mm空间群（space group），其结构为三维骨架结构。存在两个不等价的铕（Eu）位点。在第一个铕位点中，Eu采用8配位几何构型，与4个等价的金（Au）原子、8个铝（Al）原子以及4个等价的硅（Si）原子成键。所有Eu-Au键长均为3.35埃。Eu-Al键长存在4组较短的（3.40埃）与4组较长的（3.43埃）。所有Eu-Si键长均为3.37埃。在第二个铕位点中，Eu采用12配位几何构型，与8个Al原子以及8个Si原子成键。Eu-Al键长存在4组较短的（3.29埃）与4组较长的（3.44埃）；Eu-Si键长则存在4组较短的（3.31埃）与4组较长的（3.38埃）。存在两个不等价的金（Au）位点。在第一个金位点中，Au以体心立方（body-centered cubic）配位几何构型与8个Al原子成键，Au-Al键长分为4组较短的（2.61埃）与4组较长的（2.66埃）。在第二个金位点中，Au采用9配位几何构型，与4个等价的Eu原子、4个等价的Al原子以及1个Si原子成键，所有Au-Al键长均为2.59埃，Au-Si键长为2.51埃。存在三个不等价的铝（Al）位点。在第一个铝位点中，Al与2个等价的Eu原子以及4个Au原子成键，形成兼具扭曲面共享、边共享与角共享特征的AlEu₂Au₄四面体结构。在第二个铝位点中，Al与2个等价的Eu原子、2个等价的Au原子以及2个等价的Si原子成键，形成扭曲的AlEu₂Si₂Au₂四面体结构，该结构与14个AlEu₂Au₄四面体共享顶点、与4个AlEu₂Au₄四面体共享边，同时与4个等价的AlEu₂Si₂Au₂四面体共享面。其Al-Si键长均为2.58埃。在第三个铝位点中，Al与4个Eu原子以及4个Si原子成键，形成扭曲的AlEu₄Si₄四面体结构，该结构与12个AlEu₂Au₄四面体共享顶点、与6个AlEu₂Au₄四面体共享边，同时与4个等价的AlEu₄Si₄四面体共享面。其Al-Si键长均为2.58埃。存在三个不等价的硅（Si）位点。在第一个硅位点中，Si采用9配位几何构型，与4个等价的Eu原子、4个等价的Al原子以及1个Si原子成键，Si-Si键长为2.42埃。在第二个硅位点中，Si采用1配位几何构型，与4个等价的Eu原子、1个Au原子以及4个等价的Al原子成键。在第三个硅位点中，Si采用9配位几何构型，与4个等价的Eu原子、4个等价的Al原子以及1个Si原子成键。