Phosphorothionic

Phosphorothionic is a nonstandard term used in chemistry to describe chemical species that feature phosphorus–sulfur bonding. It does not designate a single well-defined compound, but rather an informal umbrella for related phosphorus–sulfur motifs, including certain oxo-thio derivatives and their esters.

Structural and chemical features commonly associated with the term include phosphorus centers bonded to sulfur through P–S single bonds, and in some cases phosphorus–sulfur multiple bonds such as P=S within thio-phosphoryl groups. The oxidation state of phosphorus in these motifs typically varies from +3 to +5, depending on the surrounding substituents and functional groups. Compounds are often discussed in the context of organophosphorus chemistry and can be generated or transformed by sulfur transfer, thiolation, or partial oxidation of phosphorus-oxygen precursors.

Related concepts and examples of related chemistry include phosphorothioates, a well-established class of organophosphorus compounds in which sulfur substitutes for an oxygen substituent on phosphorus. Phosphorothioates have found applications in agriculture as pesticides and in materials science as flame retardants. In broader coordination chemistry, phosphorus–sulfur ligands can coordinate to metal centers, expanding the range of possible reactivity and catalysis.

Safety and regulation: Many phosphorus–sulfur compounds, including those in the broader phosphorothionic vicinity, can be toxic and subject to regulatory controls. Appropriate safety measures, handling procedures, and waste disposal practices are essential.

See also: phosphorothioate, thionophosphate, phosphorus oxides.