A new Fe$^{III}$ substituted arsenotungstate [Fe$^{III}$ $_{2}$2(As$^{III}$W$_{6}$O$_{23}$)$_{2}$(As$^{III}$O$_{3}$H)$_{2}$]$^{12-}$: Synthesis, structure, characterization and magnetic properties

The iron(III)-containing arsenotungstate [Fe$^{III}$ $_{2}$2(As$^{III}$W$_{6}$O$_{23}$)$_{2}$(As$^{III}$O$_{3}$H)$_{2}$]$^{12-}$ (1) was prepared via a simple, one-pot reaction in aqueous basic medium. The compound was isolated as its sodium salt, and structurally-characterized by Single Crystal X-ray Diffraction (SCXRD), Powder X-ray Diffraction (PXRD), Fourier-Transform Infrared (FT-IR) spectroscopy, Thermogravimetric Analysis (TGA) and elemental analysis. Its magnetic properties are reported; the antiferromagnetic coupling between the two FeIII centers is unusually weak as a result of the bridging geometry imposed by the rigid arsenotungstate metalloligands.