Oxide bronzes

Molybdenum trioxide a-MoOa is also considered as a promising anode material. 

Numerous well-defined Mo triangular cluster oxide compounds exist and have been considered as possible anode materials (see ref. [22] for a review). However, the only one that has a rate capability and capacity competitive with the other materials we have considered above is Mn2Mo30g. Hierarchically nanostructured Mn2Mo30g-graphene composites (10.3 wt% carbon) consisting of graphene-wrapped 

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EXTENDING SURFACE ANALYSIS OF NEW MOSFETS BASED ON NANO AND MKM SCALED CDW PHOSPHATE AND OXIDE BRONZES... 

M. Greenblatt, Molybdenum oxide bronzes with quasi low-dimensional properties. Chem. Rev. 88 (1988) 31. 

Figure 3. SEM image of u sample of toroidal niesostruciured molybdenum oxide bronzes showing lack of any extended order in the structure.

Figure 4a. Toroidal mesostructured Mo oxide bronze before electron beam-induced transformation. Micrograph recorded at 300 KV oil a Hitachi H-9000 STEM.

Silver vanadium oxide, Ag2V4011> is a semiconducting vanadium oxide bronze which adopts at least two related structures based on V4Ou layers with silver atoms located between them (Fig. 4.17). The open structure allows facile diffusion of lithium ions. Ag2V4Oi ( can be lithiated with up to seven lithium atoms to form Li7Ag2V4Ou. 

During dyeing and rinsing, the dyeing is less sensitive to oxidation (bronzing, rubbing-fastness). 

Andersson, S. 1965. Hydrothermally grown crystals of silver vanadium oxides bronzes. Acta Chem. Scand. 19 269-270. 

Galy, J. 1992. Vanadium pentoxide and vanadium oxide bronzes — structural chemistry of single (S) and double (D) layer MxV205 phases. J. Solid State Chem. 100 229-245. 

The term insertion compound is used for solids where atoms or ions enter a three-dimensional framework without disrupting its essential structure. Many oxide bronzes are of this type, based on transition metal oxides with inserted alkali or other electropositive metals. 

Defects in perovskite oxides can be due to cation vacancies (A or B site), amon vacancies or anion excess. Cation-deficient oxides such as A,WOj give rise to oxide bronze structures, W03 itself representing the limiting case of the A-sile deficient oxide A-site vacancies are seldom ordered in these metallic systems. B-site vacancies are favoured in hexagonal perovskites and ordering of these vacancies gives rise to superstructures in some of the oxides. 

The largest series of electronically conducting materials are the phosphate tungsten bronzes. These have similar properties to oxides bronzes such as Na WOs (see Oxides Solid-state Chemistry) and are strongly colored metals or semiconductors. They are formed by inserting planes of... 

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... 

Intercalation of electroactive polymers such as polyaniline and polypyrrole in mica-type layered silicates leads to metal-insulator nanocomposites. The conductivity of these nanocomposites in the form of films is highly anisotropic, with the in-plane conductivity 10 to 10 times higher than the conductivity in the direction perpendicular to the film. Conductive polymer/oxide bronze nanocomposites have been prepared by intercalating polythiophene in V2O5 layered phase, which is analogous to clays. °° Studies of these composites are expected not only to provide a fundamental understanding of the conduction mechanism in the polymers, but also to lead to diverse electrical and optical properties. 

Solid isopoly- and heteropolymetalate compounds have been synthesized. Within this group of materials, one can include the so-called metal oxide bronzes (typically tungsten bronzes). Starting from WO, electrochemical reduction processes yield intercalation materials with electrochromic properties (Grandqvist, 1999). 

Casting metals consisting of Sb or Bi covered by a thin hydroxide layer and membranes of transition metal oxide bronzes show a relatively high selectivity for hydrogen ions, as recently reviewed by Vonau and Guth (2006). Metal/metal oxide electrodes display non-Nernstian responses, but applications in food control and medicine have... 

Fig. 3. Illustration of the effects of multiple scattering in an image of an intergrowth bismuth-tungsten oxide bronze, nominally Bio.iWOa. The simulated images shown correspond to thicknesses of 20a (near the crystal edge) and 60a respectively, with an underfocus of 1220a.

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