Materials Data on Eu(AlAu)2 by Materials Project
EuAu2Al2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Eu is bonded in a 12-coordinate geometry to eight Au and eight Al atoms. There are four shorter (3.40 Å) and four longer (3.46 Å) Eu–Au bond lengths. There are four shorter (3.41 Å) and four longer (3.47 Å) Eu–Al bond lengths. There are two inequivalent Au sites. In the first Au site, Au is bonded in a 5-coordinate geometry to four equivalent Eu and five Al atoms. There are one shorter (2.55 Å) and four longer (2.63 Å) Au–Al bond lengths. In the second Au site, Au is bonded to four equivalent Eu and four equivalent Al atoms to form distorted AuEu4Al4 tetrahedra that share corners with twelve equivalent AlEu4Au4 tetrahedra, edges with two equivalent AlEu4Au4 tetrahedra, edges with four equivalent AuEu4Al4 tetrahedra, and faces with four equivalent AuEu4Al4 tetrahedra. All Au–Al bond lengths are 2.61 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 5-coordinate geometry to four equivalent Eu and five Au atoms. In the second Al site, Al is bonded to four equivalent Eu and four equivalent Au atoms to form AlEu4Au4 tetrahedra that share corners with twelve equivalent AuEu4Al4 tetrahedra, edges with two equivalent AuEu4Al4 tetrahedra, edges with four equivalent AlEu4Au4 tetrahedra, and faces with four equivalent AlEu4Au4 tetrahedra.