The first structural characterization of the highly unsaturated dichromium carbonyl Cr-2(CO)(8) is reported using density functional theory (DFT). Cr-2(CO)(8) is predicted to have a short metal-metal bond length of 2.30 Angstrom (B3LYP) or 2.28 Angstrom (BP86). The minimum-energy structure exhibits distorted CS symmetry, with nonequivalent chromium atoms and two equivalent asymmetrically bridging carbonyls. A high-symmetry (D-2d) structure with a nominal chromium-chromium quadruple bond lies similar to22 kcal/mol higher in energy. Three other higher-energy structures are also found, including two geometries with two bridging carbonyls best interpreted as four-electron donors. The dissociation energy of Cr-2(CO)(8) to the fragments 2Cr(CO)(4) or Cr(CO)(3) plus Cr(CO)(5) is predicted to be about 34 kcal/mol (B3LYP) or 44 kcal/mol (BP86), indicating that Cr-2(CO)(8), like Cr-2(CO)(9) but unlike Cr-2(CO)(10) and Cr-2(CO)(11), is stable with respect to dissociation into its fragments.