Please use this identifier to cite or link to this item:
https://scholarbank.nus.edu.sg/handle/10635/91858
DC Field | Value | |
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dc.title | Abrupt structural transformation in hydrotalcite-like compounds mgi-jAltCOHMNOaV/zHiO as a continuous function of nitrate anions | |
dc.contributor.author | Xu, Z.P. | |
dc.contributor.author | Zeng, H.C. | |
dc.date.accessioned | 2014-10-09T09:51:30Z | |
dc.date.available | 2014-10-09T09:51:30Z | |
dc.date.issued | 2001-03-08 | |
dc.identifier.citation | Xu, Z.P.,Zeng, H.C. (2001-03-08). Abrupt structural transformation in hydrotalcite-like compounds mgi-jAltCOHMNOaV/zHiO as a continuous function of nitrate anions. Journal of Physical Chemistry B 105 (9) : 1743-1749. ScholarBank@NUS Repository. | |
dc.identifier.issn | 15206106 | |
dc.identifier.uri | http://scholarbank.nus.edu.sg/handle/10635/91858 | |
dc.description.abstract | We report here a systematic XRD/FTIR/CHN/ICP investigation for structural transformation of hydrotalcitelike compounds Mgi-jAlOHMNOaVnFhO as a continuous function of nitrate anions (x = 0.18-0.34). With seven finely divided steps in x value, a clear relationship between basal spacing and nitrate anion content (and thus trivalent cation content) has been found. In particular, we have been able to "arrest" an intermediate hydrotalcite-like phase that situates at the midpoint of an abrupt structural transformation. Unlike that of normal hydrotalcites, the relationship revealed in our nitrated Mgi-iAU(OH)2(NO3)x·H2O samples is much more complicated. While the lattice parameter a decreases with increase of nitrate content, the parameter c decreases slightly over x = 0.18-0.22, rises abruptly with a further increase of nitrate anions at x = 0.26, and then reaches maximums at x = 0.31-0.34. The compound at x = 0.26 also shows a sharp decrease in mean crystallite dimension. The abrupt structural change is attributed to a drastic change in nitrate anion arrangement. On the basis of our FTIR observations and Coulombic energy estimation, a "stick-lying" model for nitrate arrangement has been proposed, which is apparently superior to a "tilt-lying" model reported previously. The saturated charge density of the brucite-like layers for the "stick-lying" nitrate anions is about 4 e/nm2. The sharp decrease in crystallite dimension can be ascribed to the change of nitrate configuration from "flat-lying" to "stick-lying" due to increasing lateral repulsion among the anions and thus discontinuation in the planar growth. © 2001 American Chemical Society. | |
dc.source | Scopus | |
dc.type | Article | |
dc.contributor.department | CHEMICAL & ENVIRONMENTAL ENGINEERING | |
dc.contributor.department | CHEMICAL AND PROCESS ENGINEERING CENTRE | |
dc.description.sourcetitle | Journal of Physical Chemistry B | |
dc.description.volume | 105 | |
dc.description.issue | 9 | |
dc.description.page | 1743-1749 | |
dc.description.coden | JPCBF | |
dc.identifier.isiut | NOT_IN_WOS | |
Appears in Collections: | Staff Publications |
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