Structure of imidazolium hexachlorotantalate(V)

C3HsN~.(TaC16)-, Mr=462"75, ortho- rhombic, Pnma, a = 14.796(8), b=6.985(3), c = 11"011 (6)~, V =1138"0)k 3, Dx=2"701Mgm -3, Z=4, A(MoK~)=0"71069A , tz=10"92mm-l, F(000) -- 848, T = 185 K, R -- 0-042 for 847 observed reflections. The structure consists of roughly octahedral (TaC16)- anions (Ta--CI -- 2.317 (3)- 2.362 (3)A) and imidazolium cations interacting via N--H...C1 hydrogen bonds. There is also cohesion between the layers due to normal van der Waals contacts.