Kasthuri Rangan, K. ; Gopalakrishnan, J. (1994) New titanium-vanadium phosphates of nasicon and langbeinite structures, and differences between the two structures toward deintercalation of alkali metal Journal of Solid State Chemistry, 109 (1). pp. 116-121. ISSN 0022-4596
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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00224...
Related URL: http://dx.doi.org/10.1006/jssc.1994.1080
Abstract
Mixed metal phosphates of the general formula Ax TiVIII(PO4)3, where A = Na, K, or Ba and (0 < x ≤ 3), have been synthesized. While the sodium phosphate, Na3TiV(PO4)3, adopts the NASICON structure, the potassium compound, K2TiV(PO4)3, crystallizes with the langbeinite structure. BaTiV(PO4)3 is dimorphic, adopting the NASICON structure at lower temperatures and the langbeinite structure at higher temperatures. Ba1.5V2(PO4)3 and BaKV2(PO4)3, on the other hand, crystallize only with the langbeinite structure. Oxidative deintercalation of sodium from Na3TiV(PO4)3 readily occurs, yielding NaxTiV(PO4)3 (x ~ 1.0) and retaining the NASICON framework, while a similar deintercalation of potassium does not occur from the langbeinite K2TiV(PO4)3, revealing a difference in reactivity between the two structures: NASICON, being a skeleton structure with an interconnected interstitial space, facilitates mobility of alkali metal ions through the crystal, while langbeinite, being a true cage structure, does not permit a similar mobility.
Item Type: | Article |
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ID Code: | 12805 |
Deposited On: | 11 Nov 2010 08:54 |
Last Modified: | 02 Jun 2011 11:55 |
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