In an NMR spectroscopic study the cleavage of epoxides [ethylene, propylene, and cis/trans-butylene oxide] by chromyl chloride giving access to oxochromium(VI) alkoxides was shown to proceed via a bimolecular rate-determining step where two molecules of a complex CrO2Cl2···epoxide collide. Subsequently one Cl ligand at the first Cr center attacks the backside of an epoxide molecule complexed at the Cr center of a second CrO2Cl2···epoxide molecule and vice versa. The trans-opening of the epoxides was proved by determining the configuration of the chlorohydrins resulting from hydrolysis of the corresponding alkoxide products in the cases of cis- and trans-butylene oxide. The NMR data provide evidence that each oxochromium(VI) alkoxide adopts one preferred conformation in solution although DFT calculations did not indicate any special stabilizing effects. The product formation was rationalized by DFT calculations concerning the thermodynamics of the reactions.