Table 1. Physical and Thermal Properties of [C_nC₁Im][FeCl₃X] and [C_nC₁Im]₃[MCl₃X₃] Series PILs.

compound	measured density (g mL–1)a	thermal stability (°C)b	dynamic viscosity (mPa·s)c	χm (m3 mol–1) × 10–7
[C4C1Im][FeCl4]d	1.400 ± 0.032		31.1 ± 1.0	0.141
[C4C1Im][FeCl4]	1.381 ± 0.011	337	45.8 ± 2.7	0.158
[C6C1Im][FeCl4]	1.338 ± 0.013	336	49.3 ± 2.1	0.157
[C8C1Im][FeCl4]	1.230 ± 0.038	320	60.9 ± 3.4	0.153
[C4C1Im][FeCl3Br]	1.505 ± 0.004	330	37.9 ± 2.6	0.143
[C6C1Im][FeCl3Br]	1.417 ± 0.004	318	51.9 ± 3.3	0.153
[C8C1Im][FeCl3Br]	1.375 ± 0.003	309	70.1 ± 5.9	0.131
[C4C1Im]3[HoCl6]	1.882 ± 0.059	306	solid	0.602
[C6C1Im]3[HoCl6]	1.672 ± 0.021	302	solid	0.881
[C8C1Im]3[HoCl6]	1.592 ± 0.057	358	solid	1.064
[C4C1Im]3[HoCl3Br3]	1.809 ± 0.005	355	solid	0.899
[C6C1Im]3[HoCl3Br3]	1.639 ± 0.021	346	solid	0.988
[C8C1Im]3[HoCl3Br3]	1.651 ± 0.031	341	solid	0.986
[C4C1Im]3[DyCl6]	1.859 ± 0.033	366	solid	0.881
[C6C1Im]3[DyCl6]	1.749 ± 0.074	371	solid	0.910
[C8C1Im]3[DyCl6]	1.582 ± 0.043	354	solid	0.865
[C4C1Im]3[DyCl3Br3]	1.770 ± 0.025	395	solid	0.863
[C6C1Im]3[DyCl3Br3]	1.531 ± 0.015	335	solid	0.820
[C8C1Im]3[DyCl3Br3]	1.515 ± 0.037	313	solid	0.682
[C4C1Im]3[GdCl6]	1.624 ± 0.019	358	solid	0.363
[C6C1Im]3[GdCl6]	1.484 ± 0.016	333	solid	0.492
[C8C1Im]3[GdCl6]	1.724 ± 0.035	344	solid	0.562
[C4C1Im]3[GdCl3Br3]	1.724 ± 0.021	366	solid	0.540
[C6C1Im]3[GdCl3Br3]	1.592 ± 0.017	371	solid	0.492
[C8C1Im]3[GdCl3Br3]	1.703 ± 0.026	354	solid	0.585

^aDensity measured at 25 °C.

^bTGA temperature (N₂, 5 °C/min) at which 5 wt % loss of compound is observed.

^cDynamic viscosity (μ) at room temperature (25 °C).

^dAs-received commercial reference material.