2-[(Diisopropyl­thio­phosphor­yl)amino]­pyridinium tetra­fluoro­borate

The title compound, C(11)H(20)N(2)PS(+)·BF(4) (−), is a salt of 2-(diisopropyl­thio­phospho­ryl­amino)­pyridine, a chelating bidentate ligand that furnishes an S atom as a soft donor and a pyridine N atom as a hard atom for transition-metal complexation. The title salt crystallizes with two formula units in the asymmetric unit. The two independent cations are protonated at the pyridine N atoms and have the S atoms syn-oriented to them so as to form bent intra­molecular N—H⋯S hydrogen bonds, one of which one is bifurcated by involving also an N—H⋯F inter­action. The phospho­ryl­amino NH groups form near linear hydrogen bonds to proximal tetra­fluoro­borate anions. Five weak C—H⋯F and three weak C—H⋯S inter­actions link the constituents into a three-dimensional framework. As a result of the crystal packing, the two cations differ notably in conformation, as can be seen from the S—P—N—C torsion angles of −18.7 (1)° in the first and −35.1 (1)° in the second cation.