Elucidation of the correlation between the catalytic performance and the structures of active sites on inorganic materials provides insights into the chemistry of the local structures on metal oxide catalysts. Herein, fluoride-incorporated polyoxovanadate derivatives were prepared considering that their structural resemblance could clarify the reactivity of local structural differences. By the acidification of difluoride-incorporated undecavanadate [HV₁₁O₂₉F₂]⁴⁻ (V11) in the presence of ^tBuOH, difluoride-incorporated dodecavanadate [V₁₂O₃₀(O^tBu)F₂]³⁻ (V12-O^tBu) was synthesized. The reaction between V12-O^tBu and ^tBuOOH produces [V₁₂O₃₀(OO^tBu)F₂]³⁻ (V12-OO^tBu) through ligand exchange from the tert-butoxo ligand to the tert-butylperoxo ligand in a side-on fashion, which has a structure similar to that of the peroxo form of vanadium haloperoxidase. The epoxidation and bromination of alkenes proceeded through the catalytic cycle between V12-O^tBu and V12-OO^tBu.