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.