Structure of Disodium Dimolybdate Synthesized Using Thermodynamically Stable Molybdenum (VI) Oxide Clusters as Precursors

Abstract

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°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.

Olefin epoxidation with hydrogen peroxide using octamolybdate-based self-separating catalysts

“…Similarly, the Mo-O stretching Raman frequencies of solid Na 2 Mo 2 O 7 at 990 (IR), 939, 925, 881, 821 and 768 cm −1 20 can be correlated to the Mo-O bond distances 1.700, 1.772, 1.832, 1.937, 2.058 and 2.436 Å, respectively. 21 It is further noteworthy that the linear correlation is valid for both the octahedral and tetrahedral units of the anion structure.…”

Ultra‐low Sintering Temperature Microwave Dielectric Ceramics Based on Na2O‐MoO3 Binary System

“…The coordination environment and the chemical bond have a crucial influence on the sintering temperature in Na 2 O‐MoO 3 system. The bond valence for each Mo‐O bond and Na‐O bond (or bond strength) are calculated according to the expression below …”

“…The bond valence for each Mo-O bond and Na-O bond (or bond strength) are calculated according to the expression below. 22,23,27,29…”

The Structural, Lattice Dynamic, Thermodynamic, and Mechanical Characterization of Na2Mo2O7 Crystal by First‐Principles

“…The crystal structure of the primitive cell and the conventional cell with polyhedron representations of Na 2 Mo 2 O 7 is shown in Figure 1 . At room temperature, the structure of Na 2 Mo 2 O 7 is orthorhombic, which belongs to the Cmca () space group, and its lattice constants a , b, and c are 7.17, 11.83, 14.70 Å, [ 32 ] respectively. Moreover, there are four molecular formula units in a primitive cell for Na 2 Mo 2 O 7 , namely, the Wyckoff positions occupied by Na, Mo, O are 8 d and 8 f , 8 e and 8 f , 8 f and 16 g , respectively.…”