A 1D zigzag polyoxometalate [(CH3)4N]1.50H3.50[Gd(GeW11O39)(H2O)2]·2.5H2O (1) was synthesized by reaction of the monovacant polyanion [α-GeW11O39]8-with Gd3+ ions in aqueous solution and characterized by IR, UV spectra, ICP, and X-ray crystallography. X-ray single-crystal structural analysis indicated that the title compound crystallized in a monoclinic lattice, C2/c space group with a=2.8201(5), b=2.2885(3), c=2.4033(4) nm, β=123.875 (2), V=12.878(4) nm3, Z=8, R1=0.0623, wR2=0.1287. The solid-state structure of the title compound displayed an infinite one-dimensional arrangement built up of [α-GeW11O39]8-polyanions connected by GdIII cations.