A new strontium uranyl oxyfluoride, [(UO)F][Sr(HO)](NO)·HO, was synthesized under hydrothermal conditions. The single-crystal X-ray structure was determined. This compound crystallizes in the triclinic space group P1̅ (No. 2), with unit cell parameters a = 10.7925(16) Å, b = 10.9183(16) Å, c = 13.231(2) Å, α = 92.570(8)°, β = 109.147(8)°, γ = 92.778(8)°, V = 1468.1(4) Å, and Z = 2. The structure is built from uranyl-containing [Formula: see text] chains of tetrameric units of corner-sharing UOF pentagonal bipyramids. These chains are linked through trimeric strontium units to form strontium-uranyl oxyfluoride layers further assembled by nitrate groups. The interlayer space is occupied by free water molecules. This compound was characterized by spectroscopic methods, especially F NMR highlighting the many different fluoride sites. Structural relationships with other uranyl oxyfluorides were investigated through the different F/O ratios, the structural building unit, and the structural arrangement.

The present article reviews a selection of results obtained in the AREVA/CNRS/UCA joint research laboratory. It focuses on interfaces formed by uranium hexafluoride (UF 6 ) with chemical filter (purification), carbon (UF 6 storage), and metallic substrate (corrosion). As a matter of fact, along the nuclear fuel cycle, metallic surfaces of the fluorination reactors, cooling systems (for the liquefaction of UF 6 ), and storage containers are in contact with UF 6 , either in the gas or in the liquid phase. For the removal of volatile impurities before the enrichment, surface of chemical filters with a high specific surface area must be enhanced for both selectivity and efficiency. To store depleted UF 6 ( 238 U), graphite intercalation compounds are proposed and preliminary results are presented.