N-[3-(Benzyl­dimethyl­aza­nium­yl)prop­yl]-N′,N′,N′′,N′′-tetra­methyl­guanidinium bis­(tetra­phenyl­borate)

In the crystal structure of the title salt, C₁₇H₃₂N₄²⁺·2C₂₄H₂₀B⁻, the C—N bond lengths in the CN₃ unit of the guanidinium ion are 1.323 (4), 1.336 (5) and 1.337 (5) Å, indicating partial double-bond character in each. The C atom of this unit is bonded to the three N atoms in a nearly ideal trigonal–planar geometry [N—C—N angles = 117.7 (4), 120.9 (3) and 121.4 (3)°] and the positive charge is delocalized in the CN₃ plane. The bonds between the N atoms and the terminal C-methyl groups of the guanidinium moiety all have values close to a typical single bond [1.452 (5)–1.484 (6) Å]. In the crystal, C—H...π inter­actions are present between guanidinium H atoms and the phenyl rings of both tetra­phenyl­borate ions. This leads to the formation of a two-dimensional supramolecular pattern along the ab plane.