skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites

Abstract

The Dion–Jacobson double-layered perovskite, RbNdNb{sub 2}O{sub 7}, is used as a precursor to synthesize the series ANdNb{sub 2}O{sub 7} (A=H, Li, Na, K, NH{sub 4}, Ag), and (MCl)NdNb{sub 2}O{sub 7} (M=Mn, Fe, Cu) through ion-exchange reactions ≤400 °C. Thermal stability studies indicated that most of these compounds are metastable. A combination of X-ray powder diffraction and differential thermal analysis were used to determine various low temperature decomposition pathways; these pathways were very dependent on the interlayer species. Overall the ANdNb{sub 2}O{sub 7} series was found to be less stable than the corresponding lanthanides, ALaNb{sub 2}O{sub 7}. - Graphical abstract: A new series of topochemically-prepared metastable neodymium-containing layered perovskites are studied. - Highlights: • A series of new layered neodymium containing perovskites were synthesized by ion exchange. • Products were studied by variable temperature X-ray diffraction and thermal analysis. • Most of the series are metastable showing exothermic transitions on decomposition. • The Nd compounds are less stable due to the smaller size of the Nd relative to La.

Authors:
; ; ;
Publication Date:
OSTI Identifier:
22443375
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 216; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DECOMPOSITION; DIFFERENTIAL THERMAL ANALYSIS; ION EXCHANGE; NEODYMIUM; NEODYMIUM COMPOUNDS; NIOBATES; OXIDES; PEROVSKITE; PRECURSOR; STABILITY; SYNTHESIS; X-RAY DIFFRACTION

Citation Formats

Josepha, Elisha A., Farooq, Sara, Mitchell, Cinnamon M., and Wiley, John B., E-mail: jwiley@uno.edu. Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites. United States: N. p., 2014. Web. doi:10.1016/J.JSSC.2014.04.024.
Josepha, Elisha A., Farooq, Sara, Mitchell, Cinnamon M., & Wiley, John B., E-mail: jwiley@uno.edu. Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites. United States. doi:10.1016/J.JSSC.2014.04.024.
Josepha, Elisha A., Farooq, Sara, Mitchell, Cinnamon M., and Wiley, John B., E-mail: jwiley@uno.edu. 2014. "Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites". United States. doi:10.1016/J.JSSC.2014.04.024.
@article{osti_22443375,
title = {Synthesis and thermal stability studies of a series of metastable Dion–Jacobson double-layered neodymium-niobate perovskites},
author = {Josepha, Elisha A. and Farooq, Sara and Mitchell, Cinnamon M. and Wiley, John B., E-mail: jwiley@uno.edu},
abstractNote = {The Dion–Jacobson double-layered perovskite, RbNdNb{sub 2}O{sub 7}, is used as a precursor to synthesize the series ANdNb{sub 2}O{sub 7} (A=H, Li, Na, K, NH{sub 4}, Ag), and (MCl)NdNb{sub 2}O{sub 7} (M=Mn, Fe, Cu) through ion-exchange reactions ≤400 °C. Thermal stability studies indicated that most of these compounds are metastable. A combination of X-ray powder diffraction and differential thermal analysis were used to determine various low temperature decomposition pathways; these pathways were very dependent on the interlayer species. Overall the ANdNb{sub 2}O{sub 7} series was found to be less stable than the corresponding lanthanides, ALaNb{sub 2}O{sub 7}. - Graphical abstract: A new series of topochemically-prepared metastable neodymium-containing layered perovskites are studied. - Highlights: • A series of new layered neodymium containing perovskites were synthesized by ion exchange. • Products were studied by variable temperature X-ray diffraction and thermal analysis. • Most of the series are metastable showing exothermic transitions on decomposition. • The Nd compounds are less stable due to the smaller size of the Nd relative to La.},
doi = {10.1016/J.JSSC.2014.04.024},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 216,
place = {United States},
year = 2014,
month = 8
}
  • The thermal stability and decomposition pathways of six Dion-Jacobson-related double-layered perovskites, ALaNb{sub 2}O{sub 7} (A = H, Li, Na, Ag) and (ACl)LaNb{sub 2}O{sub 7} (A = Fe, Cu), are investigated. These compounds are made by low temperature (<400 deg. C) ion exchange reactions from RbLaNb{sub 2}O{sub 7}. All the compounds are low temperature phases with some of them exhibiting decomposition exotherms consistent with metastability. Decomposition temperatures and reactions pathways vary with the identity of A with most decompositions resulting in the formation of a niobate (containing A) and LaNbO{sub 4}. Results from differential scanning calorimetry and high temperature X-ray powdermore » diffraction studies are presented and structural parameters pertinent to compound stability discussed.« less
  • We demonstrate the loss of centrosymmetry via oxygen octahedral rotations in the n = 2 Dion–Jacobson family of layered oxide perovskites, A'LaB 2O 7 (A' = Rb, Cs; B = Nb, Ta). Ab initio density functional theory calculations predict that all four materials should adopt polar space groups, in contrast to the results of previous experimental studies that have assigned these materials to the centrosymmetric P4/mmm space group. Optical second harmonic generation experiments confirm the presence of a noncentrosymmetric phase at ambient temperature. Piezoresponse force microscopy experiments also show that this phase is piezoelectric. Moreover, to elucidate the symmetry-breaking andmore » assign the appropriate space groups, the crystal structure of CsLaNb 2O 7is refined as a function of temperature from synchrotron X-ray diffraction data. Above 550 K, CsLaNb 2O 7 adopts the previously determined centrosymmetric P4/mmm space group. Between 550 and 350 K, the symmetry is lowered to the noncentrosymmetric space group Amm2. Below 350 K, additional symmetry lowering is observed as peak splitting, but the space group cannot be unambiguously identified.« less
  • Research highlights: {yields} New triple-layer Dion-Jacobson layered perovskite solid solutions synthesized. {yields} New series of Ta-doped layered perovskite solid acids, HCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10}. {yields} New series of Sr-doped layered perovskite solid acids, HCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10}. {yields} Layered perovskites with highest Ta content are weaker solid acids than HCa{sub 2}Nb{sub 3}O{sub 10}. -- Abstract: Dion-Jacobson type layered perovskites such as A'Ca{sub 2}Nb{sub 3}O{sub 10} (A' = K, Rb, H) have continued to be of great interest due to their compositional variability, rich interlayer chemistry, and wide range of physical properties. In this study, we investigated the rangemore » and effects of substitutional doping of Ta{sup 5+} for Nb{sup 5+} and of Sr{sup 2+} for Ca{sup 2+} in A'Ca{sub 2}Nb{sub 3}O{sub 10}. We have prepared and characterized three new solid solutions: KCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10}, RbCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10}, and RbCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10}. These materials all readily undergo proton exchange to form two new series of hydrated solid acid phases, which in most cases can be dehydrated to form stable HCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10} and HCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10} compounds. Intercalation studies with n-hexylamine and pyridine were carried out to gauge the relative Bronsted acidities across the HCa{sub 2}Nb{sub 3-x}Ta{sub x}O{sub 10} series, and we determined that materials with the highest tantalum contents are weaker acids than the parent compound HCa{sub 2}Nb{sub 3}O{sub 10}. Preliminary intercalation studies with pyridine for the HCa{sub 2-x}Sr{sub x}Nb{sub 3}O{sub 10}.yH{sub 2}O solid acids, however, showed no significant difference in acidity with varying strontium content.« less
  • We describe transformations of the Dion-Jacobson (D-J) phases, KLaNb{sub 2}O{sub 7} and RbBiNb{sub 2}O{sub 7}, to the Aurivillius (A) phases (PbBiO{sub 2})LaNb{sub 2}O{sub 7} (1) and (PbBiO{sub 2})BiNb{sub 2}O{sub 7} (2), in a metathesis reaction with PbBiO{sub 2}Cl. Oxide 1 adopts centrosymmetric tetragonal structure (a = 3.905(1) A, c = 25.66(1) A), whereas oxide 2 crystallizes in a noncentrosymmetric orthorhombic (A2{sub 1}am) (a = 5.489(1) A, b = 5.496(2) A, c = 25.53(1) A) structure. Oxide 2 shows a distinct SHG response towards 1064 nm laser radiation. The role of La{sup 3+} versus Bi{sup 3+} in the perovskite slabs formore » the occurrence of noncentrosymmetric structure/ferroic property in these materials is pointed out.« less