Potassium diplatinum(II) tetrakispyrophosphite (abbreviated as [Pt2(pop)4]4−) is the inorganic compound with the formula K4[Pt2(HO2POPO2H)4].

The compound has a long-lived, strongly luminescent excited state, with an emission maximum at ~510 nm and a lifetime near 10 μs.

[1] The complex is prepared by heating a mixture of potassium tetrachloroplatinate and phosphorous acid:[2] Several quat salt derivatives are known.

The pair of square-planar platinum(II) centers are bridged by four pyrophosphito (HO(O)POP(O)OH2-) ligands.

The ligands interact via hydrogen bonds between the POH and P=O group.