Colorless, diamagnetic, air-stable LW(VI)O(2)(OH) [L = hydrotris(3,5-dimethylpyrazol-1-yl)borate] forms when suspensions of LW(II)I(CO)(3) in dimethyl sulfoxide are heated at 100 degrees C. The complex was characterized by microanalysis, high-resolution mass spectrometry, and IR, NMR, and EXAFS spectroscopic techniques. The complex behaves as a weak acid with a pK(a) of around 4.7. Reaction of LWO(2)(OH) with NEt(4)OMe results in the formation of colorless, diamagnetic, air-stable NEt(4)[LW(VI)O(3)], which crystallizes as a tetrahydrate. Crystals of NEt(4)[LWO(3)]. 4H(2)O are monoclinic, space group P2(1)/c, with a 18.804(4) Angstrom, b = 9.901(8) Angstrom, c = 17.447(3) Angstrom, beta = 104.35(2)degrees, and V = 3146(1) Angstrom(3) for Z = 4. The structure is composed of discrete NEt(4)(+) and fac-[LWO(3)](-) ions strung in an alternating fashion along both sides of a zigzag ladder of hydrogen-bonded water molecules (directed parallel to the b axis). The distorted-octahedral [LWO(3)](-) anions, with W-O(1) = 1.740(4) Angstrom, W-O(2) = 1.759(4) Angstrom, and W-O(3) = 1.765(4) Angstrom, are hydrogen-bonded to water molecules through two oxo groups, with WO(2).. O(5)(i) = 2.666(6) Angstrom and WO(3).. O(4)(ii) = 2.693(6) Angstrom. The EXAFS spectra of NEt(4)[LWO(3)]. 4H(2)O and LWO(2)(OH) and related complexes are diagnostic of the respective trioxo or hydroxo-dioxo centers present. Colorless, diamagnetic, ah-stable [LW(VI)O(2)](2)(mu-O) is produced in a number of reactions, including the oxidation of LW(VI)O(2)(mu-O)(WO)-O-IV(CO)L and metathesis reactions involving LW(VI)I(2)Cl. The complex exhibits NMR spectra consistent with molecular C-2 symmetry and IR bands assignable to nu(WO2) (945 and 900 cm(-1)) and nu(as)(WOW) (780 cm(-1)) vibrational modes. Crystals of [LW(VI)O(2)](2)(mu-O) are monoclinic, space group C2/c, with a = 28.112-(7) Angstrom, b = 9.538(7) Angstrom, c = 15.722(8) Angstrom, beta = 115.56(2)degrees, and V = 3802(3) Angstrom(3) for Z = 4. The dinuclear structure is composed of distorted-octahedral LWO(2) units linked by the mu-oxo ligand; the terminal W=O bond lengths are identical at 1.715(5) Angstrom, while the bridging W-O(3) distance is 1.893(1) Angstrom.