DOE OSTI2020
U2ThS5 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are two inequivalent U3+ sites. In the first U3+ site, U3+ is bonded to seven S2- atoms to form distorted edge-sharing US7 pentagonal bipyramids. There are a spread of U–S bond distances ranging from 2.65–2.88 Å. In the second U3+ site, U3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of U–S bond distances ranging from 2.82–3.02 Å. Th4+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Th–S bond distances ranging from 2.85–3.02 Å. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded to three U3+ and one Th4+ atom to form distorted SThU3 trigonal pyramids that share corners with six STh2U3 square pyramids, corners with two equivalent STh2U3 trigonal bipyramids, corners with six SThU3 trigonal pyramids, edges with three STh2U3 square pyramids, edges with two equivalent STh2U3 trigonal bipyramids, and an edgeedge with one SThU3 trigonal pyramid. In the second S2- site, S2- is bonded to three U3+ and one Th4+ atom to form distorted SThU3 trigonal pyramids that share corners with six STh2U3 square pyramids, corners with two equivalent STh2U3 trigonal bipyramids, corners with six SThU3 trigonal pyramids, edges with three STh2U3 square pyramids, edges with two equivalent STh2U3 trigonal bipyramids, and an edgeedge with one SThU3 trigonal pyramid. In the third S2- site, S2- is bonded to three U3+ and two equivalent Th4+ atoms to form distorted STh2U3 square pyramids that share corners with eight STh2U3 square pyramids, a cornercorner with one STh2U3 trigonal bipyramid, corners with four SThU3 trigonal pyramids, an edgeedge with one STh2U3 square pyramid, edges with four equivalent STh2U3 trigonal bipyramids, edges with four SThU3 trigonal pyramids, and a faceface with one STh2U3 square pyramid. In the fourth S2- site, S2- is bonded to three U3+ and two equivalent Th4+ atoms to form distorted STh2U3 trigonal bipyramids that share corners with six STh2U3 square pyramids, corners with four equivalent STh2U3 trigonal bipyramids, corners with four SThU3 trigonal pyramids, edges with six STh2U3 square pyramids, and edges with four SThU3 trigonal pyramids. In the fifth S2- site, S2- is bonded to three U3+ and two equivalent Th4+ atoms to form STh2U3 square pyramids that share corners with four equivalent STh2U3 square pyramids, corners with five equivalent STh2U3 trigonal bipyramids, corners with eight SThU3 trigonal pyramids, edges with three STh2U3 square pyramids, edges with two equivalent STh2U3 trigonal bipyramids, edges with two SThU3 trigonal pyramids, and a faceface with one STh2U3 square pyramid.