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Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study

[Image: see text] In this work, we report for the first time, the dehydration-rehydration studies of nordstrandite-derived layered double hydroxides (LDHs) of Li and Al, n-[Li–Al–X] (X = Cl(–) and NO(3)(–)) (n-nordstrandite derived). n-[Li–Al–NO(3)], an orthorhombic phase, dehydrated at 180 °C to a...

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Autores principales: Venkataraman, Kavitha, Thomas, Grace S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8851610/
https://www.ncbi.nlm.nih.gov/pubmed/35187354
http://dx.doi.org/10.1021/acsomega.1c06630
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author Venkataraman, Kavitha
Thomas, Grace S.
author_facet Venkataraman, Kavitha
Thomas, Grace S.
author_sort Venkataraman, Kavitha
collection PubMed
description [Image: see text] In this work, we report for the first time, the dehydration-rehydration studies of nordstrandite-derived layered double hydroxides (LDHs) of Li and Al, n-[Li–Al–X] (X = Cl(–) and NO(3)(–)) (n-nordstrandite derived). n-[Li–Al–NO(3)], an orthorhombic phase, dehydrated at 180 °C to a monoclinic phase. Refinement placed the NO(3)(–) ions parallel to the hydroxide layers. The dehydration showed no change in basal spacing. The monoclinic n-[Li–Al–Cl] dehydrated at 160 °C with a 0.49 Å compression in basal spacing to an orthorhombic polytype. We compared our results with the published results of their bayerite counterparts b-[Li–Al-X] (b-bayerite derived) and observed that though n-[Li–Al–X] and b-[Li–Al–X] LDHs have similar structures, their dehydrated phases are structurally different. We also report the refinement of b-[Li–Al–Cl] (DH). Previous studies attribute the basal spacing values to the (i) degree of hydration and (ii) orientation of anions in the interlayer. We observe that basal spacing is a manifestation of the symmetry of the crystal. Dehydration of nitrate intercalated LDH, which proceeds from an orthorhombic symmetry to a monoclinic symmetry with no decrease in the interlayer spacing, is attributed to sliding of the hydroxyl layers in the ab-plane due to the increase in the β value. This sliding stabilizes the interlayer through weak long-range electrostatic forces that mainly contribute to the stabilization of the layered structure at separations much larger than the effective radius of hydrogen bonds. Such stabilization would negate the need for the layers to compress, thus conserving the basal spacing in n-[Li–Al–NO(3)] (DH).
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spelling pubmed-88516102022-02-18 Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study Venkataraman, Kavitha Thomas, Grace S. ACS Omega [Image: see text] In this work, we report for the first time, the dehydration-rehydration studies of nordstrandite-derived layered double hydroxides (LDHs) of Li and Al, n-[Li–Al–X] (X = Cl(–) and NO(3)(–)) (n-nordstrandite derived). n-[Li–Al–NO(3)], an orthorhombic phase, dehydrated at 180 °C to a monoclinic phase. Refinement placed the NO(3)(–) ions parallel to the hydroxide layers. The dehydration showed no change in basal spacing. The monoclinic n-[Li–Al–Cl] dehydrated at 160 °C with a 0.49 Å compression in basal spacing to an orthorhombic polytype. We compared our results with the published results of their bayerite counterparts b-[Li–Al-X] (b-bayerite derived) and observed that though n-[Li–Al–X] and b-[Li–Al–X] LDHs have similar structures, their dehydrated phases are structurally different. We also report the refinement of b-[Li–Al–Cl] (DH). Previous studies attribute the basal spacing values to the (i) degree of hydration and (ii) orientation of anions in the interlayer. We observe that basal spacing is a manifestation of the symmetry of the crystal. Dehydration of nitrate intercalated LDH, which proceeds from an orthorhombic symmetry to a monoclinic symmetry with no decrease in the interlayer spacing, is attributed to sliding of the hydroxyl layers in the ab-plane due to the increase in the β value. This sliding stabilizes the interlayer through weak long-range electrostatic forces that mainly contribute to the stabilization of the layered structure at separations much larger than the effective radius of hydrogen bonds. Such stabilization would negate the need for the layers to compress, thus conserving the basal spacing in n-[Li–Al–NO(3)] (DH). American Chemical Society 2022-02-03 /pmc/articles/PMC8851610/ /pubmed/35187354 http://dx.doi.org/10.1021/acsomega.1c06630 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by-nc-nd/4.0/Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Venkataraman, Kavitha
Thomas, Grace S.
Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study
title Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study
title_full Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study
title_fullStr Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study
title_full_unstemmed Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study
title_short Dehydration-Rehydration Studies on Polytypes of Chloride and Nitrate Layered Double Hydroxides of Nordstrandite and Bayerite: a Comparative Study
title_sort dehydration-rehydration studies on polytypes of chloride and nitrate layered double hydroxides of nordstrandite and bayerite: a comparative study
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8851610/
https://www.ncbi.nlm.nih.gov/pubmed/35187354
http://dx.doi.org/10.1021/acsomega.1c06630
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