The matrix isolation technique has been employed to isolate several intermediates, in sequence, in the oxidation of CH3OH by CrCl2O2. Consistent with previous theoretical calculations, a hydrogen-bonded complex formed initially after twin jet deposition and was enhanced by matrix annealing to 33 K. This complex was photodestroyed by Hg are irradiation with lambda < 500 nm, and led to the production of HCl and ClCrO2OCH3. These species were also produced by room temperature reaction of the two precursors in a flow system followed by rapid matrix trapping. Heating the flow reaction zone above 150 degrees C led to destruction of ClCrO2OCH3, and production of CH2O and HCl. Above 250 degrees C bands due to CH2O were destroyed and bands due to CO and CO2 grew in. High-level density functional calculations (B3LYP/6-311G*) were carried out to identify potential intermediates in this system and to provide theoretical vibrational spectra for comparison to experiment.