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

Journal Article · Fri Jan 01 00:00:00 EST 1993 · Chemistry of Materials; (United States)

DOI:https://doi.org/10.1021/cm00025a025· OSTI ID:7073497

Gopalakrishnan, J; Uma, S; Bhat, V ^[1]

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1. Indian Institute of Science, Bangalore (India)

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.

• OSTI ID: 7073497
• Journal Information: Chemistry of Materials; (United States), Vol. 5:1; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

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
&amp; Refractories- Structure &amp; Phase Studies
400201 - Chemical &amp; Physicochemical Properties