Materials Data on EuCuSi3 by Materials Project
EuCuSi3 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Eu3+ is bonded to twelve Si+1.33- atoms to form distorted EuSi12 cuboctahedra that share corners with eight equivalent EuSi12 cuboctahedra, corners with eight equivalent CuSi4 tetrahedra, edges with four equivalent EuSi12 cuboctahedra, edges with four equivalent CuSi4 tetrahedra, and faces with four equivalent EuSi12 cuboctahedra. There are four shorter (3.19 Å) and eight longer (3.27 Å) Eu–Si bond lengths. Cu1+ is bonded to four equivalent Si+1.33- atoms to form distorted CuSi4 tetrahedra that share corners with eight equivalent EuSi12 cuboctahedra, corners with four equivalent CuSi4 tetrahedra, and edges with four equivalent EuSi12 cuboctahedra. All Cu–Si bond lengths are 2.45 Å. There are two inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 9-coordinate geometry to four equivalent Eu3+, two equivalent Cu1+, and three Si+1.33- atoms. There are one shorter (2.38 Å) and two longer (2.45 Å) Si–Si bond lengths. In the second Si+1.33- site, Si+1.33- is bonded in a 8-coordinate geometry to four equivalent Eu3+ and four equivalent Si+1.33- atoms.