N,N,N′,N′,N′′-Penta­methyl-N′′-[3-(tri­methyl­aza­nium­yl)prop­yl]guanidinium bis­(tetra­phenyl­borate)

In the crystal structure of the title salt, C₁₂H₃₀N₄²⁺·2C₂₄H₂₀B⁻, the C—N bond lengths in the central CN₃ unit of the guanidinium ion are 1.3388 (17), 1.3390 (16) and 1.3540 (17) Å, indicating partial double-bond character in each. The central C atom is bonded to the three N atoms in a nearly ideal trigonal-planar geometry 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 [1.4630 (16)–1.4697 (17) Å]. C—H...π inter­actions are present between the guanidinium H atoms and the phenyl C atoms of one tetra­phenyl­borate ion. The phenyl rings form a kind of aromatic pocket, in which the guanidinium ion is embedded.