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Title: Synthesis of layered perovskite oxides, ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs), and characterization of new solid acids, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (O < x [le] 2), exhibiting variable Bronsted acidity

Abstract

Layered perovskite oxides of the formula ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs and 0 , x [le] 2) have been prepared. The members adopt the structures of the parent ACa[sub 2]Nb[sub 3]O[sub 10]. Interlayer alkali cations in the niobium-titanium oxide series can be ion-exchanged with Li[sup +], Na[sup +], NG[sub 4][sup +], of H[sup +] to give new derivatives. Intercalation of the protonated derivatives with organic bases reveals that the Bronsted acidity of the solid solution series, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10], depends on the titanium content. While the x = 1 member (HCaLaNb[sub 2]TiO[sub 10]) is nearly as acidic as the parent HCa[sub 2]Nb[sub 3]O[sub 10], the x = 2 member (HLA[sub 2]NbTi[sub 2]O[sub 10]) is a weak acid hardly intercalating organic bases with pK[sub a] [approximately] 11.3. The variation of acidity is probably due to an ordering of Nb/Ti atoms in the triple octahedral perovskite slabs, [Ca[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10]], such that protons are attached to NbO[sub 6] octahedra in the x = 1 member and to TiO[sub 6] octahedra in the x = 2 member. 20 refs., 6 figs., 5 tabs.

Authors:
; ;  [1]
  1. Indian Institute of Science, Bangalore (India)
Publication Date:
OSTI Identifier:
7073497
Resource Type:
Journal Article
Journal Name:
Chemistry of Materials; (United States)
Additional Journal Information:
Journal Volume: 5:1; Journal ID: ISSN 0897-4756
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CALCIUM OXIDES; CHEMICAL PREPARATION; CESIUM OXIDES; INORGANIC ACIDS; LANTHANUM OXIDES; NIOBIUM OXIDES; POTASSIUM OXIDES; RUBIDIUM OXIDES; TITANIUM OXIDES; CHEMICAL REACTIONS; ION EXCHANGE MATERIALS; ALKALI METAL COMPOUNDS; ALKALINE EARTH METAL COMPOUNDS; CALCIUM COMPOUNDS; CESIUM COMPOUNDS; CHALCOGENIDES; HYDROGEN COMPOUNDS; LANTHANUM COMPOUNDS; MATERIALS; NIOBIUM COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; POTASSIUM COMPOUNDS; RARE EARTH COMPOUNDS; REFRACTORY METAL COMPOUNDS; RUBIDIUM COMPOUNDS; SYNTHESIS; TITANIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; 360202* - Ceramics, Cermets, & Refractories- Structure & Phase Studies; 400201 - Chemical & Physicochemical Properties

Citation Formats

Gopalakrishnan, J, Uma, S, and Bhat, V. Synthesis of layered perovskite oxides, ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs), and characterization of new solid acids, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (O < x [le] 2), exhibiting variable Bronsted acidity. United States: N. p., 1993. Web. doi:10.1021/cm00025a025.
Gopalakrishnan, J, Uma, S, & Bhat, V. Synthesis of layered perovskite oxides, ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs), and characterization of new solid acids, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (O < x [le] 2), exhibiting variable Bronsted acidity. United States. https://doi.org/10.1021/cm00025a025
Gopalakrishnan, J, Uma, S, and Bhat, V. 1993. "Synthesis of layered perovskite oxides, ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs), and characterization of new solid acids, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (O < x [le] 2), exhibiting variable Bronsted acidity". United States. https://doi.org/10.1021/cm00025a025.
@article{osti_7073497,
title = {Synthesis of layered perovskite oxides, ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs), and characterization of new solid acids, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (O < x [le] 2), exhibiting variable Bronsted acidity},
author = {Gopalakrishnan, J and Uma, S and Bhat, V},
abstractNote = {Layered perovskite oxides of the formula ACa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10] (A = K, Rb, Cs and 0 , x [le] 2) have been prepared. The members adopt the structures of the parent ACa[sub 2]Nb[sub 3]O[sub 10]. Interlayer alkali cations in the niobium-titanium oxide series can be ion-exchanged with Li[sup +], Na[sup +], NG[sub 4][sup +], of H[sup +] to give new derivatives. Intercalation of the protonated derivatives with organic bases reveals that the Bronsted acidity of the solid solution series, HCa[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10], depends on the titanium content. While the x = 1 member (HCaLaNb[sub 2]TiO[sub 10]) is nearly as acidic as the parent HCa[sub 2]Nb[sub 3]O[sub 10], the x = 2 member (HLA[sub 2]NbTi[sub 2]O[sub 10]) is a weak acid hardly intercalating organic bases with pK[sub a] [approximately] 11.3. The variation of acidity is probably due to an ordering of Nb/Ti atoms in the triple octahedral perovskite slabs, [Ca[sub 2-x]La[sub x]Nb[sub 3-x]Ti[sub x]O[sub 10]], such that protons are attached to NbO[sub 6] octahedra in the x = 1 member and to TiO[sub 6] octahedra in the x = 2 member. 20 refs., 6 figs., 5 tabs.},
doi = {10.1021/cm00025a025},
url = {https://www.osti.gov/biblio/7073497}, journal = {Chemistry of Materials; (United States)},
issn = {0897-4756},
number = ,
volume = 5:1,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1993},
month = {Fri Jan 01 00:00:00 EST 1993}
}