Torbernite mineral

Torbernite is a copper uranyl phosphate mineral with formula Cu(UO2)2(PO4)2(H2O)4·8H2O in the September 2026 IMA list, which gives status A and the designation 1980 s.p.; this special-procedure designation is not a numbered mineral approval identifier. Locock and Burns grew synthetic torbernite crystals at approximately 5 degrees C over two months by diffusion of phosphate and uranyl nitrate into copper-bearing silica gel, then measured an epoxy-coated crystal by room-temperature single-crystal X-ray diffraction. They refined a tetragonal P4/nnc structure with twelve water groups per formula unit and uranyl-phosphate sheets. Copper has four short bonds to coordinating water groups and two longer contacts to uranyl oxygen atoms, interpreted as Jahn-Teller-distorted (4+2) coordination. The remaining water groups form square-planar sets above and below the copper plane. The proposed hydrogen-bond network uses difference-map hydrogen positions constrained to O-H bond lengths and fixed displacement parameters. The paper presumes equivalence to natural torbernite from agreement of unit-cell dimensions; it did not analyze a natural torbernite crystal. Its separate metatorbernite, zeunerite and metazeunerite arms have different preparations and structures. In particular, eight-water metatorbernite, its twinning and 88.3(6)% copper occupancy are not torbernite results. Structural comparison with the separately prepared eight-water phase supports a distinction between hydration states but is not a direct time-resolved dehydration experiment or recovery measurement. The article references deposited observed/calculated structure factors that were not acquired in this investigation; no independent diffraction re-refinement is claimed. Torbernite is distinct from metatorbernite, the autunite group, uranyl ions and elemental uranium or copper. This laboratory structural evidence establishes neither microbial extraction nor isolated-product recovery, industrial deployment or criticality inherited from either element.

Record source: data/records/torbernite.yaml