A lithium ethyl­ene­diphos­phon­ate containing lithium chains and symmetric hydrogen bonds

In the title compound, catena‐polylithium‐μ₃‐ethyl­ene­diphos­phon­ato], Li(C₂H₇O₆P₂)]_n, the supra­molecular monoclinic (C2/c) structure consists of one‐dimensional lithium chains Li?Li = 2.7036 (8) Å] that are embedded within ethyl­ene­diphosphon­ate anions linked by strong symmetric hydrogen bonds O?O = 2.473 (3) Å]. The Li atoms and the H atom in the symmetric hydrogen bond reside on twofold rotation axes and there is an inversion center at the mid‐point of the C—C bond of the ethylenediphosphonate ligand.