As reported by the laboratory of Dominik Munz (Universität des Saarlandes) in JACS, an oxidation of triphenylphosphine can yield a stable dimer dication, that is, a compound containing a phoshorus-phosphorus bond each carrying a positive charge and each with three phenyl substituents (F. Dankert et al DOI). The oxidizing reagent to bring this about may appear outlandish: a salt of a bis(perfluorophenyl)-perfluorinated-dihydrophenazinium radical ion and an tetra(tri(trifluoromethyl)methyloxy)aluminate anion. Phenazinium radical ions are well known stable compounds for example from biochemistry. It is one in a range of often weird one-electron oxidation reagents such as ferrocenium tetrafluoroborate or magic blue. This reagent was developed in 2020 by the laboratory of Ingo Hartung at the Albert-Ludwigs-Universität Freiburg (DOI) and advertised as easy to make, "innocent" as in does not react with substrates and soluble in organic solvents. Strangely, for some reason it is also advertised as an "deelectronator" and not an oxidant but the IUPAC Goldbook is pretty stern: the term is obsolete (ref).

The aluminate counterion has plenty of trifluoromethyl groups that can shield the diphosphonium dication and the newly formed hexaphenyl-1,2-diphosphonium dication compound has two of them. It forms by dimerization of two triphenylphosphonium radical cations but unlike the triphenylmethyl radical which forms a quinoid when the radical methyl group attacks a phenyl ring, it is stable. The compound forms colorless crystals and is stable up to 260 degrees. The article describes it as a superoxidant: in reaction with trimethylphosphine it exchanges itself with triphenylphosphine. It is also a super Lewis acid. In a reaction with bis(triphenylphosphine)iminium hexafluoroantimonate it manages to steal away a fluorine atom with antimony pentafluoride considered one of the strongest Lewis acids that exist. With water (2 equivalents) an oxygen atom inserts itself between the two phosphorus atoms with simultaneous formation of 2 eq. of the protonated triphenylphosphine as the salt. The authors note a strong resemblance with the so-called Hendrickson's reagent (Ph₃P)₂O.2TfO that is made from triphenylphoshine oxide and triflic acid and has uses as a reagent in organic reactions.

If this parade of compounds strikes you as bewildering, when mister Hendrikson himself introduced his reagent as (Ph₃P(OTf)₂) back in 1975 he had it all wrong (ref) and was corrected in 1979. Even further back in 1900, Moses Gomberg was sure to have discovered the elusive hexaphenylethane by dimerization of the triphenylmethyl radical, a claim that also proven wrong (see Gomberg's dimer) in 1968.

Datasets: here and here