Two novel molybdenum(V) complexes, [Mo2O4(acac)2(gly)](EtOH)(H2O), 1, and [Mo2O4(acac)2(D,L-val)], 2, (acac = acetylacetonato, EtOH = ethanol), were synthesized by the reaction of [Mo2O3(acac)4] and amino acids glycine and D,L-valine, resp. The complexes were characterized by elemental and IR spectral anal. Their structures were detd. by the single crystal X-ray diffraction method. Both complexes are dinuclear, with singly bonded Mo-Mo in the {Mo2O4}2+ core, a carboxylato bridging amino acid, and with each Mo atom addnl. coordinated by a bidentate acetylacetonato ligand. Crystal data: C14H27Mo2NO12 (1) crystallizes in the monoclinic system, space group P21/n, with a = 8.439(2), b = 20.613(4), c = 12.639(3) .ANG., .beta. = 98.410(10), Z = 4; C15H25Mo2No10 (2) crystallizes in the orthohombic system, space group Pbca with a = 13.596(1), b = 19.346(1), c = 15.080(1) .ANG., Z = 8.