DOE OSTI2020
Th3(RuSi3)4 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded to twelve Si2- atoms to form ThSi12 cuboctahedra that share corners with four equivalent ThSi12 cuboctahedra, corners with four equivalent RuSi7 hexagonal pyramids, edges with eight equivalent ThSi12 cuboctahedra, faces with four equivalent RuSi7 hexagonal pyramids, and faces with two equivalent RuSi5 trigonal bipyramids. There are a spread of Th–Si bond distances ranging from 3.10–3.17 Å. In the second Th4+ site, Th4+ is bonded to twelve Si2- atoms to form distorted ThSi12 cuboctahedra that share corners with four equivalent ThSi12 cuboctahedra, corners with four equivalent RuSi7 hexagonal pyramids, edges with four equivalent ThSi12 cuboctahedra, edges with two equivalent RuSi7 hexagonal pyramids, faces with four equivalent ThSi12 cuboctahedra, and faces with four equivalent RuSi5 trigonal bipyramids. There are a spread of Th–Si bond distances ranging from 3.03–3.23 Å. There are two inequivalent Ru3+ sites. In the first Ru3+ site, Ru3+ is bonded to seven Si2- atoms to form distorted RuSi7 hexagonal pyramids that share corners with six ThSi12 cuboctahedra, corners with four equivalent RuSi7 hexagonal pyramids, corners with four equivalent RuSi5 trigonal bipyramids, edges with two equivalent ThSi12 cuboctahedra, an edgeedge with one RuSi7 hexagonal pyramid, and faces with two equivalent ThSi12 cuboctahedra. There are a spread of Ru–Si bond distances ranging from 2.45–2.56 Å. In the second Ru3+ site, Ru3+ is bonded to five Si2- atoms to form distorted RuSi5 trigonal bipyramids that share corners with four equivalent RuSi7 hexagonal pyramids and faces with five ThSi12 cuboctahedra. There are one shorter (2.39 Å) and four longer (2.45 Å) Ru–Si bond lengths. There are four inequivalent Si2- sites. In the first Si2- site, Si2- is bonded in a 1-coordinate geometry to four equivalent Th4+, one Ru3+, and four Si2- atoms. There are two shorter (2.48 Å) and two longer (2.50 Å) Si–Si bond lengths. In the second Si2- site, Si2- is bonded in a 9-coordinate geometry to two equivalent Th4+, three equivalent Ru3+, and four Si2- atoms. All Si–Si bond lengths are 2.65 Å. In the third Si2- site, Si2- is bonded in a 2-coordinate geometry to three Th4+, two Ru3+, and four Si2- atoms. There are one shorter (2.61 Å) and one longer (2.70 Å) Si–Si bond lengths. In the fourth Si2- site, Si2- is bonded in a 2-coordinate geometry to three Th4+, two Ru3+, and four Si2- atoms.