(But-oxy-methyl-idene)di-methyl-aza-nium tetra-phenyl-borate aceto-nitrile monosolvate.

In the title solvated salt, C7H16NO(+)·C24H20B(-)·C2H3N, the C-N bond lengths in the cation are 1.2831 (19), 1.467 (2) and 1.465 (2) Å, indicating double- and single-bond character, respectively. The C-O bond length of 1.2950 (18) Å shows a double-bond character, pointing towards charge delocalization within the NCO plane of the iminium ion. The two C atoms of the n-butyl group are disordered over the two sites, with refined occupancy ratios of 0.890 (5):0.110 (5) and 0.888 (4):0.112 (4). In the crystal, C-H⋯π inter-actions occur between the methine H atom, H atoms of the -N(CH3)2 and -CH2 groups of the cation, and two of the phenyl rings of the tetra-phenyl-borate anion. The latter inter-action forms an aromatic pocket in which the cation is embedded. Thus, a two-dimensional pattern is created in the ac plane.