Reactions between alumina and sodium hydroxide in ethylene glycol result in the formation of aluminoglycolate anions. Al-27 NMR studies have been carried out to assist in their characterization, and aluminum species in tetra-, penta-, and hexacoordinate geometries have been detected. X-ray diffraction studies of crystalline products confirm the formation of pentacoordinate dianions; two crystalline forms of a 2:1 Na:A1 complex have been isolated, containing different amounts of solvent molecules. The compound Na2Al(OCH2CH2O)(2)OCH2CH2OH . 4HOCH(2)CH(2)OH (1) crystallizes in space group P (1) over bar, with a = 8.062(2) Angstrom, b = 8.660(2) Angstrom, c 17.257(3) Angstrom; alpha 99.78(3)degrees, beta = 97.61(3)degrees, gamma = 97.08(3)degrees, Z = 2 at 130 K; Na2Al(OCH2CH2O)(2)OCH2CH2OH . 5HOCH(2)CH(2)OH (2) crystallizes in space group P (1) over bar, with a = 8.479(3)degrees, b = 19.557(5)degrees, c = 16.641(5) Angstrom; alpha = 90.48(3)degrees, beta = 96.68(2)degrees, gamma = 89.22(2)degrees, and Z = 4 at 291 K. A third complex isolated has a 1:1 Na:A1 ratio and contains a trimeric aluminum species consisting of two pentacoordinate and one hexacoordinate aluminum geometries : Na3Al3(OCH2CH2O)(5)(OCH2CH2OH)(2).6HOCH(2)CH(2)OH (3) crystallizes in space group P2(1)/c, with a = 9.531(2) Angstrom, b = 21.490(4) Angstrom, c = 22.298(4) Angstrom, beta = 99.41(3)degrees, and Z = 4 at 130 K. The intermolecular binding in the three structures involves extensive hydrogen bonding between coordinated and free glycolate molecules coupled with close cation ... O ionic contacts. The Al-O bond distance for the monobasic glycolates is significantly shorter than the fully coordinated bond distances (means 1.783(9), 1.846(28) Angstrom), though ionic contacts also perturb the coordination geometries.