Li ₃ UHO ₃ : A Uranium Hydride Oxide

High Resolution Image Download MS PowerPoint Slide Li 3 UHO 3, the first crystallographically characterized uranium hydride oxide (oxyhydride), was synthesized via a salt-flux reaction of UO 2 with excess LiH at 973 K as a brown, air-sensitive solid. Single-crystal X-ray diffraction reveals a novel coloring variant of the rocksalt structure ( Pm 3 m ) in which oxide and hydride anions form a cubic close-packing and U 4+ /Li + cations fill alternating octahedral voids. The edge-sharing [LiH 2 O 4 ] and [UO 6 ] octahedra yield ordered anion positions. Li–O distances are consistent with related hydride oxides, whereas Li–H separations are unusually long, reflecting weaker hydride coordination within edge-sharing octahedra. 1 H/ 7 Li MAS NMR and CHN analyses confirm H – incorporation. Li 3 UHO 3 thus extends heteroanionic hydride chemistry into the actinide series.