Oxyfluorinated compounds with an open structure XVI. Synthesis, structure determination and magnetic properties of Fe4F3(PO4)(HPO4)4(H2O)4(N2C3H12) [ULM-15]

Fe 4 F 3 (PO 4 )(HPO 4 ) 4 (H 2 O) 4 (N 2 C 3 H 12 ) (labelled ULM-15) was prepared hydrothermally (7 days, 453 K, autogenous pressure) in the presence of 1,3-diaminopropane as organic template. Its structure was determined by single crystal X-ray diffraction. ULM-15 is monoclinic (Space group C 2/ c (no 15)) with lattice parameters a = 24.176(1) , b = 14.558(1) , c = 7.186(1) , β = 102.3(1)°, V = 2470.8(3) 3 , Z = 4. Its three-dimensional framework is constituted from corner-sharing FeX 6 (X = O, F, H 2 O) octahedra and tetrahedral PO 4 and HPO 4 groups. The structure presents trans-chains of FeO 4 F 2 octahedra related to ferric dimers [Fe 2 O 8 F 2 (H 2 O) 2 ] by tetrahedral units. They delimit 16-membered rings channels along [001] in which the diprotonated amines are inserted. ULM-15 shows 3D antiferromagnetic behaviour below T N ≈ 22 K.