title: 1-Butyl-3-ethyl-1H-benzimidazol-3-ium tetra-fluoro-borate.
abstract: In the title salt, C(13)H(19)N(2) (+)·BF(4) (-), an ionic liquid, the butyl and ethyl substituents bonded to the N atoms of the imidazole ring [r.m.s. deviation = 0.019 (1) Å] adopt equatorial positions. The crystal structure exhibits slipped π-π inter-actions between the imidazole and benzene rings of neighbouring mol-ecules [centroid-centroid distance = 3.529 (2) Å]. In the tetra-fluoro-borate anion, the B and F atoms are disordered over two sets of sites with site-occupancy factors of 0.813 (7) and 0.187 (7).
authors.affiliation: Department of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001,  USA.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Junge
authors.forename: Derek R
authors.initials: DR
authors.lastname: Scadova
authors.forename: James A
authors.initials: JA
authors.lastname: Golen
authors.forename: Jerry P
authors.initials: JP
authors.lastname: Jasinski