High-Pressure Synthesis and Characterization of the Actinide Borate Phosphate U2[BO4][PO4]

A new actinide borate phosphate, U2[BO4][PO4], was synthesized in a Walker‐type multianvil apparatus at 12.5 GPa and 1000 °C. The crystal structure was determined from single‐crystal X‐ray diffraction data collected at room temperature. U2[BO4][PO4] crystallizes in the monoclinic space group P21/c with four formula units per unit cell and the lattice parameters a = 854.6(2), b = 775.3(2), c = 816.3(2) pm, and β = 102.52(3)°. The structure consists of double layers of linked uranium–oxygen polyhedra parallel to [100]. The borate tetrahedra are located between the uranium–oxygen layers inside the double layer. The phosphate groups link the double layers. U2[BO4][PO4] is the first uranium borate phosphate synthesized under high‐pressure/high‐temperature conditions (12.5 GPa and 1000 °C). The new actinide borate phosphate crystallizes in the monoclinic space group P21/c with four formula units per unit cell. The crystal structure consists of isolated [BO4]5– and [PO4]3– groups and double layers formed by uranium and oxygen atoms.