Room temperature vs high temperature synthesis of hydrogen bronzes of niobium derived from the layered perovskites ALaNb{sub 2}O{sub 7} (A=H,Na,K)
- Institut de Ciencia de Materials de Barcelona (CSIC), Barcelona (Spain)
A series of layered perovskites of general formula AA`{sub n{minus}1}Nb{sub n}O{sub 3n+1} (n=2,3,4, A= alkaline ion, A`=Ca,La) have been reported to exchange easily the ion A{sup +} by other smaller alkaline ions or protons. These processes take place with overall conservation of the charge in the layered host. The authors have prepared the previously reported members with n=2 NaLaNb{sub 2}O{sub 7}, KLaNb{sub 2}O{sub 7} and the proton-exchanged derivative HLaNb{sub 2}O{sub 7}. The authors have found that a reductive intercalation of additional protons is possible for the latter under reducing conditions to yield a {open_quotes}blue{close_quotes} derivative H{sub 1+x}LaNb{sub 2}O{sub 7}, where the Nb ion is partly reduced to Nb(IV). This species can be considered as a blue hydrogen bronze of niobium. When carried out at room temperature, the reduction is reversible and the blue compound gets easily reoxidized in air. On the other hand, a reduction process carried out at 650{degrees}C yields an equally blue but much more stable reduced species. The paper will also present the results of cation-doping synthesis of the sodium and potassium oxides. Other details of the synthesis and properties of these oxides will be presented.
- OSTI ID:
- 141065
- Report Number(s):
- CONF-930304-; TRN: 93:003688-0738
- Resource Relation:
- Conference: 205. American Chemical Society national meeting, Denver, CO (United States), 28 Mar - 2 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of 205th ACS national meeting; PB: 1951 p.
- Country of Publication:
- United States
- Language:
- English
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