Oxygen species in Ni and Cu octahedral molecular sieves (OMS) having a 2 x 2 tunnel structure similar to that of cryptomelane or hollandite have been studied in detail through stepwise-ramping temperature-programmed reduction in CO/He, as compared to constant-ramping temperature-programmed reduction. The availability, recoverability, and structural stability of lattice oxygen in Ni-OMS-2 and Cu-OMS-2 were studied by means of monitoring the isothermal reduction and oxidation with CO/He and O-2/He, respectively, in combination with X-ray diffraction studies. Results suggest there is a much higher resolution of oxygen species with a stepwise-ramping temperature-programmed technique. Quantitation of uptake and loss of oxygen to and from the lattice shows increasing mobility with increasing temperature of reduction/oxidation. The mobility decreases with subsequent redox cycles. The structure of OMS-2 survives to a certain extent following the redox cycle but collapses more severely at higher temperature. A compromise was chosen for maximum recoverability of oxygen and for minimum damage to crystallographic structure.