Canted Antiferromagnetism in Two-Dimensional Silver(II) Bis[pentafluoridooxidotungstate(VI)]

By slow reaction between colorless AgIW2O2F9 and elemental F2 in liquid anhydrous HF, violet platelike single crystals of Ag(WOF5)2 were grown. The crystal structure of Ag(WOF5)2 consists of layers built from Ag2+ cations bridged by [WOF5]− anions and not, as previously assumed, from infinite [AgII–F]+∞ chains and [W2O2F9]− anions. A majority (97\%) of the disordered AgII cations are found with square-planar coordination of F/O ligands within the same layer, and they form additional long contacts with O/F atoms originating from the neighboring layers. The remaining 3\% the of Ag(II) ions are coordinated only by F atoms in a square-planar fashion. The magnetic moments of Ag2+ from the same layer are almost perfectly antiferromagnetically aligned. Weak ferromagnetic interlayer interactions cause a small tilt (∼1.5°) of the magnetic moments, resulting in canted antiferromagnetism. Because of the lowering of the symmetry of [WOF5]− in the solid state, the vibrational spectra show more bands than expected for regular C4v symmetry. The electronic spectrum of Ag(WOF5)2 is reported and analyzed.