The structure of disodium dimolybdate (Na2Mo2O7) synthesized by a low-temperature method in the process of ultrasonic spray pyrolysis using acidified aqueous solutions of thermodynamically stable molybdenum (VI) oxide clusters as a precursor was refined down to an R-factor of 7%. The refinement of the diffraction data showed that Na2Mo2O7 powder synthesized at 300 degrees C belongs to the base-centered orthorhombic type of structure with a space group of Cmca (no. 64). It was found that the basic units of the octahedral MoO6 precursor complexes exist in the structure of Na2Mo2O7. Tetrahedral MoO4 building units that coexist together with octahedral units in the structure of Na2Mo2O7 are most likely developed by the termination of weak octahedral bonds and by the placement of the molybdenum atom in the center of the tetrahedra.