DOE OSTI2020
U4TeSe7 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are four inequivalent U4+ sites. In the first U4+ site, U4+ is bonded in a 9-coordinate geometry to one Te2- and eight Se2- atoms. The U–Te bond length is 3.28 Å. There are a spread of U–Se bond distances ranging from 2.84–3.17 Å. In the second U4+ site, U4+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.25 Å. In the third U4+ site, U4+ is bonded in a 9-coordinate geometry to two equivalent Te2- and seven Se2- atoms. Both U–Te bond lengths are 3.18 Å. There are a spread of U–Se bond distances ranging from 2.87–3.34 Å. In the fourth U4+ site, U4+ is bonded in a 9-coordinate geometry to two equivalent Te2- and seven Se2- atoms. Both U–Te bond lengths are 3.30 Å. There are a spread of U–Se bond distances ranging from 2.85–3.10 Å. Te2- is bonded in a 7-coordinate geometry to five U4+ and two equivalent Se2- atoms. Both Te–Se bond lengths are 3.31 Å. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four U4+ atoms to form distorted corner-sharing SeU4 tetrahedra. In the second Se2- site, Se2- is bonded to four U4+ atoms to form distorted corner-sharing SeU4 tetrahedra. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to four U4+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to four U4+ and two equivalent Te2- atoms. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U4+ atoms. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U4+ atoms. In the seventh Se2- site, Se2- is bonded in a 5-coordinate geometry to five U4+ atoms.