Preparation of new selenium-rich selenides, CrSe3, MoSe≈5, WSe≈6–7, and ReSe≈6–7 and known selenides, by the reaction of metal carbonyls with selenium

Abstract

The reaction of the transition-metal carbonyls, Cr(CO)₆, Mn₂(CO)₁₀, Fe(CO)₅, Co₂(CO)₈, Mo(CO)₆, W(CO)₆ and Re₂(CO)₁₀, with selenium in 1,2-dichlorobenzene heated under reflux produced a number of known transition-metal Selenides, MnSe, MnSe₂, FeSe₂, CoSe₂, MoSe₂ and WSe₂ and four new selenium-rich compounds, CrSe₃, MoSe_≈5, WSe_≈6–7 and ReSe_≈6–7. The new selenides, with high selenium-to-metal ratios, were obtained as amorphous solids, while the known compounds, MnSe, MnSe₂, FeSe₂, CoSe₂ were formed as polycrystalline powders and MoSe₂ and WSe₂ as poorly ordered fibres. The products were characterised by analytical electron microscopy and powder X-ray diffraction and MoSe_≈5 was further characterised using thermal methods.