Digitale Medien
Springer
Journal of sol gel science and technology
13 (1998), S. 65-70
ISSN:
1573-4846
Schlagwort(e):
vanadates
;
hydrothermal syntheses
;
vanadium oxide gels
;
VV precursors
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract A wide range of polyvanadates can be synthesized from aqueous solutions. Vanadium oxide gels V2O5 · nH2O are formed around the point of zero charge (pH ≈2). They exhibit a ribbon-like structure. Weak interactions between these ribbons lead to the formation of mesophases in which vanadium oxide gels or sols behave as nematic liquid crystals. Organic species can be easily intercalated between these oxide ribbons leading to the formation of hybrid nanocomposites made of alternative layers of organic and inorganic components. Hybrid materials can also be formed at a higher pH in the presence of large organic ions such as [N(CH3)4]+. They exhibit layered structures in which organic cations lie between polyoxovanadate planes. Such layered structures are not obtained in the presence of anions such as Cl− or I−. Cluster shell polyvanadates are then formed. They are made of negatively charged polyvanadate hollow spheres in which the negative anion is encapsulated. In this case the organic cations behave as counter ions for the formation of the hybrid crystalline network.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1008647120784
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