Structures of hexachloroniobate(V) salts of the 1-methylimidazole/1-methylimidazolium and 2-methylimidazolium cations

Both salts contain approximately octahedral [NbCl 6 ] - anions with Nb-Cl bond lengths ranging from 2.326 (2) to 2.378 (2) A. The 1 -methylimidazole salt (I) contains the proton-bridged 1-methylimidazole/1 -methylimidazolium cation, whereas the fully N-protonated 2-methylimidazolium ion is present in the 2-methylimidazole compound (II). Cohesion in the crystals is achieved by dipolar interactions between Cl atoms of [NbCl 6 ] - and imidazole C-H groups for (I) and (II), as well as N-H...Cl hydrogen bonds for (II)