Pyridinium di­hydrogenmono­thio­phosphate

By reaction of pyridine di­thio­monometa­phospho­ryl fluoride with ethyl­di­phenyl­phosphine in the presence of traces of water, we isolated crystals of the title compound, (I). In the structure of this salt, two kinds of hydrogen bonds were detected. They link N—H (part of the cation), as well as one O—H group (part of the anion), to the phospho­ryl O atom of the anion. The donor–acceptor distances are 2.654 (1) and 2.568 (1) Å, respectively. The P—O and P—S bond lengths are 1.514 (2) and 1.967 (1) Å, respectively, which fall therefore in the range of a 1.5‐fold bond.