Ruthenium(IV) fluoride

Ruthenium(IV) fluoride is a binary inorganic compound of ruthenium and fluorine with the formula RuF4.

Synthesis
The compound was first prepared in 1963 by Holloway and Peacock, who obtained a yellow solid by reducing ruthenium pentafluoride with iodine, using iodine pentafluoride as a solvent.


 * 10RuF5 + I2 -> 10RuF4 + 2IF5

Subsequent studies have indicated that produced by this way is impure. The pure, pink compound was isolated for the first time in 1992 by reacting with Arsenic pentafluoride at 20 °C in anhydrous hydrofluoric acid, with strict exclusion of water and oxygen. This synthesis exploits the very strong fluoride ion accepting capabilities of the Lewis acid.


 * K2RuF6 + 2AsF5 -> RuF4 + 2KAsF6

Physical properties
in the solid state is polymeric, with a three-dimensional structure of corrugated layers containing RuF6 octahedra joined by shared fluorine atoms. The crystalline structure is similar to that of vanadium tetrafluoride and is monoclinic, space group P21/n, with lattice constants a = 560.7 pm, b = 494.6 pm, and c =514.3 pm, β = 121.27°.

Ruthenium tetrafluoride is an extremely reactive compound which darkens immediately upon contact with moisture, and reacts violently with water to deposit ruthenium dioxide. The compound can be stored in glass containers, which are, however, attacked if the sample is heated above 280 °C.