Substitution of the internal AsO<sup>3–</sup> ligand in complex [{Re<sub>4</sub>As<sub>2</sub>(AsO)<sub>2</sub>}(CN)<sub>12&

The reaction of the tetrahedral rhenium arsenide cluster K8[{Re4As2(AsO)2}(CN)12] with molten KF · HF is studied. The reaction affords complex K6[{Re4As2(AsO)F}(CN)12] · 3H2O · KF (I). The substitution of one (µ3-AsO)3– ligand by µ3-F– is shown to occur during the reaction, and the remained internal ligands are not involved in the reaction. The phase purity of the synthesized compound and the absence of impurities of different compositions are confirmed by phase X-ray diffraction (XRD) and mass spectrometry. The structure of complex I is determined by single-crystal XRD (CIF file CCDC no. 2362544).