The monomolecular films of diacylic diperoxides on the water/air interface were studied. Their general formula: CH₃-(CH₂)_m-C(O)-O-O-C(O)-(CH₂)_n-C(O)-O-O-C(O)-(CH₂)_m-CH_3. The behavior of monomolecular films of diperoxides are affected by the structure of their molecule. The numerical values of the areas of molecules that are extrapolated to zero pressure are different. This indicates a different conformation of the molecules in the monolayer. The optimal geometric structure of the molecule of diperoxide, the total area (S), the volume (V), the heat of formation (∆_fH²⁹⁸), the energy of higher occupied (E_HOMO) and the lower vacant (E_LUMO) molecular orbitals were obtain in the calculations. The optimal geometric structures of peroxides and their electronic properties were calculated by the quantum-chemical method. Calculations of conformational states of the molecule of diperoxides are carried out. Experimental data and quantum-chemical calculations are consistent with each other.