(PyH)(5)[(MoOCl4)-O-V(H2O)](3)Cl-2 and (PyH)(n)[(MoOBr4)-O-V](n) reacted with glycolic acid (H(2)glyc) or its half-neutralized ion (Hglyc(-)) to afford a series of novel glycolato complexes based on the {(Mo2O4)-O-V}(2+) structural core: (PyH)(3)[Mo2O4Cl4(Hglyc)] center dot 1/2CH(3)CN (1), (PyH)(3)[Mo2O4Br4(Hglyc)] center dot (PrOH)-O-j (2), (PyH)(2)[Mo2O4(glyc)(2)Py-2] (3), (PyH)(4)[Mo4O8Cl4(glyc)(2)] center dot 2EtOH (4), and [Mo4O8(glyc)(2)Py-4] (5) (Py = pyridine, C5H5N; PyH+ = pyridinium cation, C5H5NH+ and glyc(2-) = a doubly ionized glycolate, -OCH2COO-). The compounds were fully characterized by X-ray crystallography and infrared spectroscopy. The Hglyc(-) ion binds to the {Mo2O4}(2+) core through a carboxylate end in a bidentate bridging manner, whereas the glyc(2-) ion adopts a chelating bidentate coordination through a deprotonated hydroxyl group and a monodentate carboxylate. The orientations of glyc(2-) ions in 3-5 are such that the alkoxyl oxygen atoms occupy the sites opposite the multiply bonded oxides. {(C6H5)(4)P}[(MoO2)-O-VI(glyc)(Hglyc)] (6), an oxidized complex, features a reversed orientation of the glyc(2-) ion. The theoretical DFT calculations on the [(Mo2O4)-O-V(glyc)(2)Py-2](2-) and [(MoO2)-O-VI(glyc)(2)](2-) ions confirm that binding of glycolate with the alkoxyl oxygen to the site opposite the Mo=O bond is energetically more favorable in {(Mo2O4)-O-V}(2+) species, whereas a reversed orientation of the ligand is preferred in Mo(VI) complexes. An explanation based on the orbital analysis is put forward.