title: Synthesis, structure, and spectroscopy of two ternary uranium(IV) thiophosphates: UP2S9 and UP2S7 containing P2S9(2-) and P2S7(2-) ligands.
abstract: The two ternary uranium thiophosphate compounds were isolated from polychalcogenide flux reactions. UP2S9 crystallizes in the tetragonal space group P42/mcm with two formula units per unit cell, where a = 7.762(1) and c = 9.691(3) Å. UP2S7 crystallizes in the orthorhombic space group Fddd with 16 formula units per unit cell, here a = 8.919(3), b = 15.198(4), and c = 30.104(9) Å. Both compounds were characterized through single crystal X-ray, UV-vis-NIR, and Raman spectroscopy. The structures of the two compounds are formed from [US6](8-) chains connected to each other by either the tridentate-chelating P2S9(4-) in UP2S9 or the P2S7(4-) in UP2S7 resulting in 3D frameworks. These two ligands have different geometries, but they exhibit similar coordination modes, comparable to the ethane-like P2S6(4-). The uranium cations in both compounds can be assigned an unambiguous oxidation state of +4. The two compounds are semiconductors with nearly identical band-gaps of 1.41 eV.
authors.affiliation: Department of Civil & Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Babo
authors.forename: Laurent
authors.initials: L
authors.lastname: Jouffret
authors.forename: Jian
authors.initials: J
authors.lastname: Lin
authors.forename: Eric M
authors.initials: EM
authors.lastname: Villa
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Albrecht-Schmitt