Magnetic ligands in the Pt₂(dta)₄I compound

We report a reinterpretation of the electronic structure of the $(Pt)_2I(dta)_4$ compound, based on {\em ab initio} embedded fragment calculations. Our major results are the following. First, the usually assumed electronic intra-dimer charge ordering is unrealistic. Second, the $(dta)$ ligands take part actively in the magnetic properties of the system. The proposed electronic structure is favorably confronted to experimental data. In particular, the unexplained $3:1$ $Pt^{2+}/Pt^{3+}$ abundances ratio of the XPS spectra is rationalized.