Room temperature molten fluorometallates: 1-ethyl-3-methylimidazolium hexafluoroniobate(V) and hexafluorotantalate(V)

The first room temperature molten salts containing hexafluorometallate anions of transition metals, 1-ethyl-3-methylimidazolium (EMIm) hexafluoroniobate, EMImNb(V)F6, and hexafluorotantalate, EMImTa(V)F6, have been synthesized by the reactions of EMImF·2.3HF with NbF5 and TaF5, respectively. They exhibit similar physical properties. Viscosities and conductivities are 49 cP and 8.5 mS cm−1 for EMImNbF6 and 51 cP and 7.1 mS cm−1 for EMImTaF6, respectively at 298 K.