Sodium tungsten oxide

X > 0.28, this results in metalhc conductivity (Goodenough, 1965 Greenblatt, 1996). Nonstoichiometric sodium tungsten oxide (x < 1) has a distorted perovskite stmcture with unequal W-O bond lengths and tilted WOe octahedra. 

Sodium tungsten oxide (Na2 4) Sodium silicate (ifei2Si20g) Sodium silicate (Na2Si20g) Sodium silicate (Na2Si20g) Sodium sulfide (Na2S)... 

The Raman investigation of niobium species in aqueous solutions of niobium oxalate (Jehng and Wachs, 1991) nicely showed the dependence of their constitution on pH and concentration. The PZC theory was successfully applied to predict the hydrated, molecular structures of multicomponent supported metal oxide species, such as iron-molybdenum, iron-vanadium, molybdenum-vanadium, tungsten-vanadium, and sodium-vanadium oxide species (Vuurman et al., 1991 Wachs et al., 1993). 

W(CN)j /W(CN)j, and Fe3"/Fe2+ in acid solutions [90,91], Simple ETR at sodium tungsten bronzes, NaxW03, with the perovskite structure are fast and are influenced by the sodium bulk content of the electrode as can be seen in Table 2. Unfortunately, the kinetic pattern is not simple because the variation of ETR rate coefficients with sodium content is not the same for each couple [91]. A qualitative interpretation of the ETR kinetic results has been attempted in terms of the density of electronic states at the Fermi level of the oxide electrode [90]. 

Introduction of sodium into empty 12-coordinate sites of the WO3 lattice results in a series of oxide bronzes. These have general formula NaxWOa, where 0.0sodium tungsten bronzes retain the monoclinic structure of the parent WO3 and they are n-type semiconductors [276,277]. With increasing Na content the structure evolves through two distinct tetragonal phases and for x>0.43 the bronzes adopt an essentially cubic perovskite structure [278] closely related to that of ReOs (fig. 18). The Na 3s levels lie about 10 eV above the bottom of the W 5d bands and each added Na atom is therefore ionised to Na, with donation of one electron into the W 5d band of local t2g symmetry [279]. For x values of less than 0.26, the 5d electrons are localised, probably by an interplay between polaronic effects, disorder... 

Sodium tetrachloroaluminate (NaAlCl ) Sodium tetrafluoroaluminate (NaAlF ) Sodium tetrahydroborate (NaBH ) Sodiun tungsten oxide (Na2W0 ) Stroniun oxide (SrO)... 

The sodium tungsten bronzes already described are examples of incomplete lattice defect structures. Iron(II) oxide is rather similar it has a rock-salt structure but is always deficient in iron. Some Fe ions are always present to maintain electrical neutrality. Fe304 has the spinel structure which has the same arrangement of ions as FeO. Fe203. has also the same arrangement and oxidation of FeO to FcgOg consists of the replacement of Fe2+ ions by two thirds of their number of Fe ions. 

Molten Carbonate Fuel Cells (MCFCs) The development of molten carbonate fuel cells (MCFCs) started in 1951, when Boers and Ketlaar built a fuel cell with a mixture of sodium carbonate and tungsten oxide as electrolyte later they changed it to a mixture of lithium,... 

---