Crystal structure of 2-di­methyl­amino-1-eth­oxy­carbonyl-3-methyl-3,4,5,6-tetra­hydro­pyrimidin-1-ium tetra­phenyl­borate

The asymmetric unit of the title salt, C(10)H(20)N(3)O(2) (+)·C(24)H(20)B(−), contains two cations and two tetra­phenyl­borate ions. The C—N bond lengths in the central CN(3) unit of the guanidinium ions range between 1.323 (2) and 1.381 (2) Å, indicating partial double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN(3) plane. The cationic six-membered rings are nonplanar, the dihedral angles between the N/C/N and C/C/C planes ranging from 45.8 (1) to 53.6 (1)°. In the crystal, C—H⋯π inter­actions are present between the guanidinium H atoms and the phenyl rings of the tetra­phenyl­borate ions. The phenyl rings form aromatic pockets, in which the guanidinium ions are embedded.