1：Experimental Design and Method Selection:

A one-step hydrothermal synthesis was employed to grow single crystals of BaMoOF5, utilizing an in-situ reduction to reduce molybdenum from Mo(VI) to Mo(V). The method was chosen for its versatility in synthesizing solid-state products under mild conditions.

2：Sample Selection and Data Sources:

Reagents included Ba(CH3CO2)2, MoO3, UO2(CH3CO2)2, and HF, used as received. The synthesis targeted the Ba-U-Mo-F phase space due to high molybdenum content in nuclear waste streams.

3：List of Experimental Equipment and Materials:

PTFE liner, stainless steel autoclave, programmable convection oven, Bruker D8 QUEST diffractometer with PHOTON 100 CMOS area detector and Incoatec microfocus source (Mo Kα radiation, λ = 0.71073 ?), SAINT+, SADABS, SHELXS, SHELXL-2014, ShelXle interface, Structure Tidy program.

4：71073 ?), SAINT+, SADABS, SHELXS, SHELXL-2014, ShelXle interface, Structure Tidy program. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Reagents (1 mmol each) were added to 1 mL distilled water in a PTFE liner, followed by slow addition of 1 mL HF. The liner was capped, placed in an autoclave, and heated in an oven to 200°C at 10°/min, held for 24 h, cooled to 40°C at 0.1°/min, then to room temperature naturally. Crystals were collected by vacuum filtration, washed with water and acetone, and dried under vacuum.

5：1°/min, then to room temperature naturally. Crystals were collected by vacuum filtration, washed with water and acetone, and dried under vacuum. Data Analysis Methods:

5. Data Analysis Methods: Single-crystal X-ray diffraction data were collected at 300 K, reduced and corrected using SAINT+ and SADABS. Structure solution and refinement were performed with SHELXS and SHELXL-2014, with bond valence calculations and atomic coordinate standardization using Structure Tidy.