Two new organically templated U(IV) fluorides, (C 5 H 14 N 2 ) 2 U 2 F 12 ‚2H 2 O (AU1-1) and (C 2 H 10 N 2 )U 2 F 10 (AU2-1), have been prepared from the reaction of UO 3 with HF and homopiperazine (C 5 H 12 N 2 ) at 200 °C in aqueous media. These compounds have been characterized by single-crystal X-ray diffraction, elemental analysis, and magnetic susceptibility measurements. Crystallographic data: AU1-1, monoclinic, space group P2 1 /c, a ) 9.272(4) Å, b ) 12.314(4) Å, c ) 18.475(7) Å, β ) 90.32(3)°, Z ) 4; AU2-1, monoclinic, space group C2/c, a ) 16.038(8) Å, b ) 7.131(3) Å, c ) 8.782(4) Å, β ) 91.75(4)°, Z ) 4. AU1-1 consists of face-sharing UF 9 tricapped trigonal prisms that form one-dimensional chains that further hydrogen-bond with diprotonated homopiperazine and water molecules. AU2-1 forms, in part, from the cleavage of homopiperazine to yield diprotonated ethylenediamine, which serves to template the formation of uranium fluoride layers. These layers consist of edge-and corner-sharing UF 9 tricapped trigonal prisms. The variable-temperature magnetic susceptibility of AU1-1 is consistent with antiferromagnetic interactions between U(IV) centers, with µ eff (300 K) ) 4.37 µ B /f.u. and θ ) -1.3 K. The magnetization of AU1-1 at 2 K displays an irreversible metamagnetic-like transition at H c ) 3.60 T. The magnetic susceptibility for AU2-1 (µ eff (300 K) ) 4.58 µ B /f.u.) with θ ) +21 K suggests the presence of weak ferromagnetic interactions within the [U 2 F 10 ] 2layers.

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