Studies in Non-stoichiometry: Magnetic Susceptibilities in the Tungsten-Oxygen System¹

Abstract

Magnetic susceptibilities have been measured by the Gouy method for several tungsten oxides oE the series WO,. At 297.5"K. the susceptibility per unit volume is found t o increase n~o~~otonically from -0.65 X lope to +0.46 X 10-o as x in WO, decreases from 3 to 2. Results are interpretable in terms of a defect structure in which 3x oxygen atoms have been removed from a host WO, lattice leaving 2(3x) rlectrons iii the conduction band of the host. Quantitative agreement with a Pauli-Peierls calcrrlation is surprisingly good. The model may be applicable to other non-stoichiometric oxides for which "mixetl-oxidation-state" structures have been postulated.

Magnetic susceptibility and thermoelectric power of tungsten intermediary oxides

“…susceptibilities per gram formula weight W03-J are given in table 2. It is of interest to compare our results with those reported by Sienko and Banerjee [19]. They obtained x(W02.15) = 4.06 x emu mol-', x(wO2.87) = -7.11 x IOu6 emu mol-' and x(WO3) = -21.0 x emu mol-'.…”

The Anodic Oxidation of Tungsten in Aqueous Base

“…Figure 4 reveals that in all solutions except VIII and IX, a dislocation occurred at low current densities. This behavior has been observed by other investigators (1,5,34) and has been attributed to the influence of the potential of zero charge (pzc) of the metal (35). The author is unaware of data for this medium for tungsten, so that no firm conclusion here is possible.…”

“…The oxides WO2 and WO8 crystallize in the same manner; both have tetragonal and rhombic space groups. In fact, the coordination of tungsten in both oxides is octahedral and magnetic susceptibility data (34) indicate that the substoichiometric oxides between WO2 and WO3 are perhaps best represented by a surplus of free electrons in the conduction band from defects or vacancies in the WO3 structure. Thought of in these terms, no monomeric representation of the W(V) intermediate could correctly describe it.…”

Superconductivity in the tungsten bronzeRbxWO3(0.20⩽x⩽<

“…These values are about two times larger than expected from a freeelectron band containing x electron per W atom and it is also what is observed, on average, in the other alkali tungsten bronzes. 36 The composition dependence of x , which would result only from the x dependence of spin , is plotted in Fig. 2.…”