DOI: 10.17188/1748107
title: Materials Data on FeCu4 by Materials Project

description: FeCu4 is alpha La-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Fe is bonded to six equivalent Fe and six equivalent Cu atoms to form FeFe6Cu6 cuboctahedra that share corners with six equivalent FeFe6Cu6 cuboctahedra, corners with six CuCu12 cuboctahedra, edges with six equivalent FeFe6Cu6 cuboctahedra, edges with eighteen CuFe3Cu9 cuboctahedra, faces with six equivalent FeFe6Cu6 cuboctahedra, and faces with twelve equivalent CuFe3Cu9 cuboctahedra. All Fe–Fe bond lengths are 2.55 Å. All Fe–Cu bond lengths are 2.57 Å. There are seven inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Fe and nine Cu atoms to form CuFe3Cu9 cuboctahedra that share corners with twelve CuFe3Cu9 cuboctahedra, edges with six equivalent FeFe6Cu6 cuboctahedra, edges with eighteen CuFe3Cu9 cuboctahedra, faces with six equivalent FeFe6Cu6 cuboctahedra, and faces with twelve CuFe3Cu9 cuboctahedra. There are six shorter (2.55 Å) and three longer (2.56 Å) Cu–Cu bond lengths. In the second Cu site, Cu is bonded to twelve Cu atoms to form CuCu12 cuboctahedra that share corners with three equivalent FeFe6Cu6 cuboctahedra, corners with nine CuFe3Cu9 cuboctahedra, edges with three equivalent FeFe6Cu6 cuboctahedra, edges with twenty-one CuFe3Cu9 cuboctahedra, and faces with eighteen CuFe3Cu9 cuboctahedra. There are six shorter (2.55 Å) and three longer (2.56 Å) Cu–Cu bond lengths. In the third Cu site, Cu is bonded to twelve Cu atoms to form CuCu12 cuboctahedra that share corners with three equivalent FeFe6Cu6 cuboctahedra, corners with nine CuFe3Cu9 cuboctahedra, edges with three equivalent FeFe6Cu6 cuboctahedra, edges with twenty-one CuFe3Cu9 cuboctahedra, and faces with eighteen CuFe3Cu9 cuboctahedra. There are six shorter (2.55 Å) and three longer (2.56 Å) Cu–Cu bond lengths. In the fourth Cu site, Cu is bonded to twelve Cu atoms to form CuCu12 cuboctahedra that share corners with three equivalent FeFe6Cu6 cuboctahedra, corners with nine CuCu12 cuboctahedra, edges with three equivalent FeFe6Cu6 cuboctahedra, edges with twenty-one CuCu12 cuboctahedra, and faces with eighteen CuCu12 cuboctahedra. There are six shorter (2.55 Å) and six longer (2.56 Å) Cu–Cu bond lengths. In the fifth Cu site, Cu is bonded to twelve Cu atoms to form CuCu12 cuboctahedra that share corners with three equivalent FeFe6Cu6 cuboctahedra, corners with fourteen CuCu12 cuboctahedra, edges with three equivalent FeFe6Cu6 cuboctahedra, edges with nineteen CuFe3Cu9 cuboctahedra, and faces with twenty-one CuFe3Cu9 cuboctahedra. There are six shorter (2.55 Å) and six longer (2.56 Å) Cu–Cu bond lengths. In the sixth Cu site, Cu is bonded to sixteen Cu atoms to form CuCu16 cuboctahedra that share corners with three equivalent FeFe6Cu6 cuboctahedra, corners with nineteen CuFe3Cu9 cuboctahedra, edges with three equivalent FeFe6Cu6 cuboctahedra, edges with twenty-one CuFe3Cu9 cuboctahedra, and faces with thirty-four CuCu12 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.55–5.10 Å. In the seventh Cu site, Cu is bonded to three equivalent Fe and nine Cu atoms to form CuFe3Cu9 cuboctahedra that share corners with seventeen CuFe3Cu9 cuboctahedra, edges with six equivalent FeFe6Cu6 cuboctahedra, edges with sixteen CuFe3Cu9 cuboctahedra, faces with six equivalent FeFe6Cu6 cuboctahedra, and faces with fifteen CuCu16 cuboctahedra. All Cu–Fe bond lengths are 2.57 Å. All Cu–Cu bond lengths are 2.55 Å.