Aphosphoryl group is atrivalent>P(=O)− group, consisting of aphosphorus atom (symbol P) and anoxygen atom (symbol O), where the three freevalencies are on the phosphorus atom. While commonly depicted as possessing a double bond (P=O) the bonding is in fact non-classical.[1]
Despite that, the meaning of the term "phosphoryl" varies, depending on the branch ofscientific discipline. For example, inbiology,biochemistry andbiomedicine branches, the term "phosphoryl" refers to groups consisting of phosphorus atom attached to three oxygen atoms, with the simplifiedchemical formula−PO3 (there are several groups called "phosphoryl" in those branches, with the chemical formulas−P(=O)(−O−)2,−P(=O)(−O−)(−OH),−P(=O)(−OH)2,−P(=O)(−O−)−O−,−P(=O)(−OH)−O− and−P(=O)(−O−)2). In the branches mentioned above, the "phosphoryl" andphosphate groups are sometimes abbreviated by the letter "P", or represented by a symbol of encircled letter "P".[2][3] "Phosphoryl" groups arecovalently bonded by asingle bond to anorganic molecule,phosphate group(s) or another "phosphoryl" group(s), and those groups aresp3 hybridized at the phosphorus atom.[4] The term "phosphoryl" in the mentioned branches is usually used in the description of catalytic mechanisms in living organisms. The "phosphoryl" group plays a central role inphosphorylation. Inbiochemical reactions involving phosphate groups (e.g. adenosine triphosphate), a "phosphoryl" group is usually transferred between thesubstrates by the "phosphoryl transfer reactions" (seephosphorylation). Examples of molecules containing those groups in biology, biochemistry and biomedicine areadenosine monophosphate (AMP),adenosine diphosphate (ADP),adenosine triphosphate (ATP),phosphocreatine (PCr) andDNA.
Contrary tobiology,biochemistry andbiomedicine branches, inorganic andinorganic chemistry branches, and in the branch ofchemical nomenclature (seeIUPAC), the correct name for the−P(=O)(−O−)2 group is not "phosphoryl", butphosphonato, and the correct name for the−P(=O)(−OH)2 group isphosphono, and the termphosphoryl correctly refers to the trivalent >P(=O)− group.[2][5] Example of molecules containing that trivalent phosphoryl group arephosphoryl chloride (O=P(−Cl)3),methylphosphonyl dichloride (O=P(−CH3)(−Cl)2) andphosphoramide (O=P(−NH2)3).
A phosphoryl group should not be confused with aphosphate group.
