New Ionic Liquid Compounds Based on Tantalum Pentachloride TaCl5: Synthesis, Structural, and Spectroscopic Elucidation of the (mu-Oxido)-Chloridotantalates(V) [BMPy][TaCl6], [BMPy](4)[(TaCl6)(2)(Ta2OCl10)], and [EMIm](2)[Ta2OCl10]

l-Butyl-4-methylpyridinium hexachloridotantalate(V), [BMPy][TaCl6] (1), tetrakis(l-butyl-4-methylpyridinium) bis(hexachloridotantalate(V) (mu-oxido)-decachloridotantalate(V), [BMPy](4)[(TaCl6)(2)(Ta2OCl10] (2), and bis(l-ethyl-3-methylimidazolium)-(mu-oxido)-decachloridoditantalate(V), [EMlm](2)[Ta2OCl10] (3) were synthesized and characterized by single-crystal X-ray diffraction and vibrational spectroscopy. Compounds 1 and 3 crystallize in the monoclinic space group P2(1)/c: (no. 14), whereas compound 2 crystallizes in the triclinic space group P (1) over bar (no. 2). All compounds are built up by the mentioned bulky organic cations and octahedral [TaCl6](-) respective linear [Ta2OCl10](2-) anions. Coulomb interactions are dominant between the ionic species. FT-IR and FT-Raman spectra were recorded and interpreted, especially with respect to the inorganic species [TaCl6](-) (O-h) and [Ta2OCl10](2-) (C-i symmetry, approximately D-4h). The melting temperatures of compounds 1-3 are given.