Rhenium complexes oxide fluorides

The NO + MF, (except NO -f WF,) reactions proceed spontaneously at 20°. The reactions were followed tensimetrically. Gaseous products were identified by infrared spectroscopy and the solid products were examined by. y-ray powder-photography. Both ReF, and OsF, formed NO+[MF,] (cub.) salts and neither salt could be induced to combine with more NO to yield the quadrivalent (NO),MF, compound. In their reactions with nitrosyl fluoride at 20°, however, the rhenium and osmium fluorides are clearly differentiated ReF, readily forms a thermally stable 2 1 adduct, which is isomorphous with (NOjjWFg, whereas the OsF, -i- ONF reaction is complex. The identification of small quantities of nitrogen oxide trifluoride, in the gaseous product of the reaction, indicate the existence of an... 

The addition of oxygen anions (in the form of highly soluble calcium oxide or lithium and sodium oxides) in the NaCl-NaF eutectic melt containing rhenium leads to a decrease in the height of waves corresponding to the discharge of rhenium from the fluoride complexes, while at more negative potentials, two extra waves appear (Fig. 6a and 6b). 

Although a number of complex fluorides of quinquevalent iridium, (e.g. KIrF,) are known, previous attempts to establish the simple fluoride have failed. The absence of a pentafluoride of iridium has become increasingly anomalous as the pentafluorides of the neighbouring elements, rhenium, osmium, and platinum have been prepared. Previous work - indicated that reactions which might have yielded the pentafluoride gave the tetrafluoride instead. The physical properties of this tetrafluoride. (m.p. 106—107 b.p. > 300 ), however, resembled those of a pentafluoride or oxide tetrafluoride. This indicated that iridium tetrafluoride differed structurally from its neighbouring tetrafluorides. 

We have studied the electrochemical behaviour of chloride, fluoride, and oxofluoride compounds of rhenium and established the conditions for the stabilization of Re(III), Re(IV), Re(VI), and Re(VII) complexes. For a more rigorous elucidation of interrelations between the redox potentials, the composition of melts, and the oxidation state of rhenium, it is necessaiy to undertake spectroelectrochemical investigations. Rhenium coatings with a thickness up to 2 mm on graphite and noble metal substrates were produced. 

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