DOE OSTI2020
Tm2Co17 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded in a 12-coordinate geometry to eighteen Co atoms. There are a spread of Tm–Co bond distances ranging from 2.92–3.25 Å. In the second Tm site, Tm is bonded in a 2-coordinate geometry to twenty Co atoms. There are a spread of Tm–Co bond distances ranging from 2.87–3.12 Å. There are four inequivalent Co sites. In the first Co site, Co is bonded in a 2-coordinate geometry to one Tm and thirteen Co atoms. There are a spread of Co–Co bond distances ranging from 2.32–2.66 Å. In the second Co site, Co is bonded to two equivalent Tm and ten Co atoms to form CoTm2Co10 cuboctahedra that share corners with twenty-two CoTm2Co10 cuboctahedra, edges with ten CoTm3Co9 cuboctahedra, and faces with eighteen CoTm2Co10 cuboctahedra. There are four shorter (2.39 Å) and four longer (2.40 Å) Co–Co bond lengths. In the third Co site, Co is bonded to two Tm and ten Co atoms to form a mixture of distorted face, edge, and corner-sharing CoTm2Co10 cuboctahedra. There are a spread of Co–Co bond distances ranging from 2.32–2.52 Å. In the fourth Co site, Co is bonded to three Tm and nine Co atoms to form a mixture of distorted face, edge, and corner-sharing CoTm3Co9 cuboctahedra. Both Co–Co bond lengths are 2.42 Å.