DOE OSTI2020
(FeCo)3Ge2 crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are three inequivalent Fe sites. In the first Fe site, Fe is bonded in a body-centered cubic geometry to four Co and four Ge atoms. There are one shorter (2.41 Å) and three longer (2.43 Å) Fe–Co bond lengths. There are one shorter (2.44 Å) and three longer (2.51 Å) Fe–Ge bond lengths. In the second Fe site, Fe is bonded in a distorted body-centered cubic geometry to seven Co and four Ge atoms. There are a spread of Fe–Co bond distances ranging from 2.42–2.87 Å. There are one shorter (2.41 Å) and three longer (2.48 Å) Fe–Ge bond lengths. In the third Fe site, Fe is bonded in a 8-coordinate geometry to seven Co and four Ge atoms. There are a spread of Fe–Co bond distances ranging from 2.53–2.80 Å. There are three shorter (2.47 Å) and one longer (2.56 Å) Fe–Ge bond lengths. There are three inequivalent Co sites. In the first Co site, Co is bonded in a 8-coordinate geometry to five Fe, three equivalent Co, and six Ge atoms. All Co–Co bond lengths are 2.55 Å. There are three shorter (2.77 Å) and three longer (2.92 Å) Co–Ge bond lengths. In the second Co site, Co is bonded in a 8-coordinate geometry to seven Fe, one Co, and six Ge atoms. The Co–Co bond length is 2.52 Å. There are three shorter (2.82 Å) and three longer (2.93 Å) Co–Ge bond lengths. In the third Co site, Co is bonded in a 4-coordinate geometry to six Fe, four Co, and four Ge atoms. There are three shorter (2.45 Å) and one longer (2.50 Å) Co–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a body-centered cubic geometry to five Fe and nine Co atoms. In the second Ge site, Ge is bonded in a distorted body-centered cubic geometry to seven Fe and seven Co atoms.