DOE OSTI2020
Co2(GeS)3 is Hausmannite-derived structured and crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are four inequivalent Co sites. In the first Co site, Co is bonded to three equivalent Ge and three equivalent S atoms to form CoGe3S3 octahedra that share corners with six equivalent CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. All Co–Ge bond lengths are 2.33 Å. All Co–S bond lengths are 2.24 Å. In the second Co site, Co is bonded to three equivalent Ge and three equivalent S atoms to form CoGe3S3 octahedra that share corners with six equivalent CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–58°. All Co–Ge bond lengths are 2.33 Å. All Co–S bond lengths are 2.24 Å. In the third Co site, Co is bonded to three Ge and three S atoms to form CoGe3S3 octahedra that share corners with six CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are two shorter (2.32 Å) and one longer (2.34 Å) Co–Ge bond lengths. There are a spread of Co–S bond distances ranging from 2.24–2.27 Å. In the fourth Co site, Co is bonded to three Ge and three S atoms to form CoGe3S3 octahedra that share corners with six CoGe3S3 octahedra, corners with six GeCo2S2 tetrahedra, and corners with six SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are two shorter (2.32 Å) and one longer (2.34 Å) Co–Ge bond lengths. There are one shorter (2.24 Å) and two longer (2.26 Å) Co–S bond lengths. There are four inequivalent Ge sites. In the first Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–71°. There are one shorter (2.42 Å) and one longer (2.58 Å) Ge–S bond lengths. In the second Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 69–73°. There are one shorter (2.41 Å) and one longer (2.58 Å) Ge–S bond lengths. In the third Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 69–73°. There are one shorter (2.42 Å) and one longer (2.58 Å) Ge–S bond lengths. In the fourth Ge site, Ge is bonded to two Co and two S atoms to form distorted GeCo2S2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four GeCo2S2 tetrahedra, corners with six SCo2Ge2 tetrahedra, and an edgeedge with one GeCo2S2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–72°. There are one shorter (2.42 Å) and one longer (2.60 Å) Ge–S bond lengths. There are four inequivalent S sites. In the first S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–75°. In the second S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 68–75°. In the third S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 67–73°. In the fourth S site, S is bonded to two Co and two Ge atoms to form distorted SCo2Ge2 tetrahedra that share corners with four CoGe3S3 octahedra, corners with four SCo2Ge2 tetrahedra, corners with six GeCo2S2 tetrahedra, and an edgeedge with one SCo2Ge2 tetrahedra. The corner-sharing octahedra tilt angles range from 67–73°.