N,N,N',N'-Tetra-methyl-guanidinium tetra-phenyl-borate.

In the title salt, C5H14N3(+)·C24H20B(-), the C-N bond lengths in the central CN3 unit are 1.3322 (11), 1.3385 (12) and 1.3422 (12) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal-planar geometry [N-C-N angles = 119.51 (8), 119.81 (9) and 120.69 (8)°] and the positive charge is delocalized in the CN3 plane. The bond lengths between the N atoms and the terminal methyl groups all have values close to a typical single bond [1.4597 (12)-1.4695 (13) Å]. The crystal packing is caused by electrostatic inter-actions between cations and anions.