Computer simulation of the structure and thermodynamic properties of Na{sub 2}O-WO{sub 3} oxides

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Inorganic Materials

OSTI ID:35530

Belashchenko, D K ^[1]

---

1. Moscow Institute of Steel and Alloys (Russian Federation)

In this paper, an investigation is carried out for noncrystalline (liquid and amorphous) sodium tungstates (Na{sub 2}O){sub x}(WO{sub 3}){sub 1-x}. In the Na{sub 2}O-WO{sub 3} system, several intermediate compounds form; glasses are produced at x = 0.30-0.44. The structure of glasses with x = 0.333 and 0.4 has been studied using pulsating-neutron-beam scattering. The nearest-neighbor W-O distance is estimated to be 0.18 nm; the next-nearest-neighbor W-O distance is 0.21 nm. It was suggested that tetrahedral (WO{sub 4}) and octahedral (WO{sub 6}) ion groups are characteristic of the structure of these glasses. The distance of 0.18 nm is encountered in all these groups, whereas the distance of 0.21 nm occurs only in the octahedra. The Na-O and O-O distances are estimated to be 0.24 and 0.28 nm, respectively. The density of glasses with x = 0.333 and 0.4 is 5.36 and 5.21 g/cm{sup 3}, respectively. In this paper, models of amorphous (vitreous) and liquid oxides (Na{sub 2}O){sub x}(WO{sub 3}){sub 1-x} (x = 0, 0.2, 0.4, 0.6, and 0.8) are constructed by the continuous static relaxation (CSR) and molecular dynamics (MD) methods for the temperatures 0 and 2000 K. The models at 0 K correspond to the amorphous state of mixed oxides; the models at 2000 K correspond to the liquid state.

• OSTI ID: 35530
• Journal Information: Inorganic Materials, Journal Name: Inorganic Materials Journal Issue: 7 Vol. 30; ISSN 0020-1685; ISSN INOMAF
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPUTERIZED SIMULATION
SODIUM TUNGSTATES
STOICHIOMETRY
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 1000-4000 K
THERMODYNAMIC PROPERTIES