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

Title: Syntheses and Characterizations of Complex Perovskite Oxynitrides LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9

Abstract

The following complex oxynitride perovskites have been prepared: LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9. Synchrotron X-ray powder diffraction analyses show that LaMg1/3Ta2/3O2N and LaMg1/2Ta1/2O5/2N1/2 are isostructural to the oxide La2Mg(Mg1/3Ta2/3)O6 (space group P21/n), whereas BaSc0.05Ta0.95O2.1N0.9 has a simple cubic symmetry similarly to BaTaO2N. The orderings of octahedral cations are markedly diminished in the above oxynitrides, as compared with the related oxides such as La2Mg(Mg1/3Ta2/3)O6 and Ba2ScTaO6. The optical band gaps are similar for the homologous compositions, LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2 and LaTaON2 (1.9 eV), and BaSc0.05Ta0.95O2.1N0.9 and BaTaO2N (1.8 eV), while the absorption edges become broader for the complex derivatives. As revealed from the impedance spectroscopic analysis, the oxynitrides have clearly different dielectric components from those of comparable oxides containing Ta5+. Impedance spectroscopy reveals interesting capacitor geometry in BaSc0.05Ta0.95O2.1N0.9 in which the semiconducting oxynitride grains are separated by insulating secondary phases. Most notably BaSc0.05Ta0.95O2.1N0.9 has a bulk component with a high relative permittivity ({kappa}=7300) and the grain boundary component with an even higher {kappa}.

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
959913
Report Number(s):
BNL-82899-2009-JA
Journal ID: ISSN 0022-4596; JSSCBI; TRN: US1005836
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 11
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 43 PARTICLE ACCELERATORS; ABSORPTION; CAPACITORS; CATIONS; DIELECTRIC MATERIALS; DIFFRACTION; GEOMETRY; IMPEDANCE; OXIDES; PERMITTIVITY; PEROVSKITE; PEROVSKITES; SPECTROSCOPY; SYMMETRY; SYNCHROTRONS; national synchrotron light source

Citation Formats

Kim,Y., and Woodward, P. Syntheses and Characterizations of Complex Perovskite Oxynitrides LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.08.031.
Kim,Y., & Woodward, P. Syntheses and Characterizations of Complex Perovskite Oxynitrides LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9. United States. doi:10.1016/j.jssc.2007.08.031.
Kim,Y., and Woodward, P. Mon . "Syntheses and Characterizations of Complex Perovskite Oxynitrides LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9". United States. doi:10.1016/j.jssc.2007.08.031.
@article{osti_959913,
title = {Syntheses and Characterizations of Complex Perovskite Oxynitrides LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9},
author = {Kim,Y. and Woodward, P.},
abstractNote = {The following complex oxynitride perovskites have been prepared: LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2, and BaSc0.05Ta0.95O2.1N0.9. Synchrotron X-ray powder diffraction analyses show that LaMg1/3Ta2/3O2N and LaMg1/2Ta1/2O5/2N1/2 are isostructural to the oxide La2Mg(Mg1/3Ta2/3)O6 (space group P21/n), whereas BaSc0.05Ta0.95O2.1N0.9 has a simple cubic symmetry similarly to BaTaO2N. The orderings of octahedral cations are markedly diminished in the above oxynitrides, as compared with the related oxides such as La2Mg(Mg1/3Ta2/3)O6 and Ba2ScTaO6. The optical band gaps are similar for the homologous compositions, LaMg1/3Ta2/3O2N, LaMg1/2Ta1/2O5/2N1/2 and LaTaON2 (1.9 eV), and BaSc0.05Ta0.95O2.1N0.9 and BaTaO2N (1.8 eV), while the absorption edges become broader for the complex derivatives. As revealed from the impedance spectroscopic analysis, the oxynitrides have clearly different dielectric components from those of comparable oxides containing Ta5+. Impedance spectroscopy reveals interesting capacitor geometry in BaSc0.05Ta0.95O2.1N0.9 in which the semiconducting oxynitride grains are separated by insulating secondary phases. Most notably BaSc0.05Ta0.95O2.1N0.9 has a bulk component with a high relative permittivity ({kappa}=7300) and the grain boundary component with an even higher {kappa}.},
doi = {10.1016/j.jssc.2007.08.031},
journal = {Journal of Solid State Chemistry},
number = 11,
volume = 180,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • The following complex oxynitride perovskites have been prepared: LaMg{sub 1/3}Ta{sub 2/3}O{sub 2}N, LaMg{sub 1/2}Ta{sub 1/2}O{sub 5/2}N{sub 1/2}, and BaSc{sub 0.05}Ta{sub 0.95}O{sub 2.1}N{sub 0.9}. Synchrotron X-ray powder diffraction analyses show that LaMg{sub 1/3}Ta{sub 2/3}O{sub 2}N and LaMg{sub 1/2}Ta{sub 1/2}O{sub 5/2}N{sub 1/2} are isostructural to the oxide La{sub 2}Mg(Mg{sub 1/3}Ta{sub 2/3})O{sub 6} (space group P2{sub 1}/n), whereas BaSc{sub 0.05}Ta{sub 0.95}O{sub 2.1}N{sub 0.9} has a simple cubic symmetry similarly to BaTaO{sub 2}N. The orderings of octahedral cations are markedly diminished in the above oxynitrides, as compared with the related oxides such as La{sub 2}Mg(Mg{sub 1/3}Ta{sub 2/3})O{sub 6} and Ba{sub 2}ScTaO{sub 6}. The opticalmore » band gaps are similar for the homologous compositions, LaMg{sub 1/3}Ta{sub 2/3}O{sub 2}N, LaMg{sub 1/2}Ta{sub 1/2}O{sub 5/2}N{sub 1/2} and LaTaON{sub 2} (1.9 eV), and BaSc{sub 0.05}Ta{sub 0.95}O{sub 2.1}N{sub 0.9} and BaTaO{sub 2}N (1.8 eV), while the absorption edges become broader for the complex derivatives. As revealed from the impedance spectroscopic analysis, the oxynitrides have clearly different dielectric components from those of comparable oxides containing Ta{sup 5+}. Impedance spectroscopy reveals interesting capacitor geometry in BaSc{sub 0.05}Ta{sub 0.95}O{sub 2.1}N{sub 0.9} in which the semiconducting oxynitride grains are separated by insulating secondary phases. Most notably BaSc{sub 0.05}Ta{sub 0.95}O{sub 2.1}N{sub 0.9} has a bulk component with a high relative permittivity ({kappa}=7300) and the grain boundary component with an even higher {kappa}. - Graphical abstract: Phase diagram showing the relations among composition and crystal structure in the quaternary La-Mg-Ta-O-N system.« less
  • Carboxylic acid (HORc)-modified Ti(OR){sub 4} products were used to study the effect that similarly ligated species with substantially varied structures have on the final densification of the resultant ceramic (in this case TiO{sub 2}). The 1:1 stoichiometric products isolated from the reactions of [Ti({mu}-ONep)(ONep){sub 3}]{sub 2} (1, ONep = OCH{sub 2}CMe{sub 3}) and a variety of sterically hindered carboxylic acids [HORc: HOFc (HO{sub 2}CH), HOAc (HO{sub 2}CCH{sub 3}), HOPc (HO{sub 2}CCHMe{sub 2}), HOBc (HO{sub 2}CCMe{sub 3}), or HONc (HO{sub 2}CCH{sub 2}CMe{sub 3})] were identified by single-crystal X-ray diffraction and solid-state {sup 13}C MAS NMR spectroscopy at Ti{sub 3}({mu}{sub 3}-O)(OFc){sub 2}(ONep){submore » 8} (2), Ti{sub 3}({mu}{sub 3}-O)(OAc){sub 2}(ONep){sub 8} (3), Ti{sub 6}({mu}{sub 3}-O){sub 6}(OPc){sub 6}(ONep){sub 6} (4), Ti{sub 2}({mu}-OBc){sub 2}(ONep){sub 6} (5), and Ti{sub 3}({mu}{sub 3}-O)(ONc){sub 2}(ONep){sub 8} (6). Compounds 2, 3, and 6 adopt a triangular arrangement of Ti atoms linked by a {mu}{sub 3}-oxide moiety with ORc and ONep ligands supporting the basic framework. Compound 4 adopts a distorted, hexagon-prism geometry of two offset [Ti-O-]{sub 3} rings with each six-coordinated metal possessing a terminal ONep and two monodentate OPc ligands. The unique, nonesterified product 5 is dimeric with two {mu}-ONep, two unidentate bridging OBc, and two terminal ONep ligands. The solution behaviors of 2--6 were investigated by NMR experiments and were found to retain the solid-state structure in solution with a great deal of ligand rearrangement. Films of TiO{sub 2} were made from redissolved crystals of 2--6. The highest density TiO{sub 2} thin films were derived from the partially hydrolyzed, trinuclear, low-carbon-containing ONep complexes 2 and 3, as determined from ellipsometric data.« less
  • The trinuclear compound Hg{sup II}(CH{sub 2}P(S)Ph{sub 2}){sub 2}(Au{sup I}Cl){sub 2} (2) was synthesized by the reaction of Hg{sup II}(CH{sub 2}P(S)Ph{sub 2}){sub 2} (1) with 2 equiv of Au(THT)Cl (THT = tetrahydrothiophene) in a CH{sub 2}Cl{sub 2} solution. Oxidation of 2 by 1 equiv of C{sub 6}H{sub 5}ICl{sub 2} yielded the mixed-valence trinuclear compound Hg{sup II}Au{sup I}(CH{sub 2}P(S)Ph{sub 2}){sub 2}Au{sup III}Cl{sub 4} (3). The crystal structures of 2 and 3 were determined by single-crystal X-ray diffraction analyses. 2 and 3 have one-dimensional chain structures in the solid. Crystal data: 2, C{sub 26}H{sub 24}HgAu{sub 2}Cl{sub 2}S{sub 2}P{sub 2}{center dot}{sup 1}/{sub 2}C{sub 5}H{submore » 12}, space group P{bar 1}, a = 11.930 (4) {angstrom}, b = 13.452 (4) {angstrom}, c = 10.516 (4) {angstrom}, {alpha} = 108.44 (2){degree}, {beta} = 90.61 (3){degree}, {gamma} = 81.06 (2){degree}, V = 1580.1 (8) {angstrom}{sup 3}, Z = 2, R = 0.0432 and R{sub w} = 0.0489 for refinement of 154 least-squares parameters with 2,744 reflections (F{sub {degree}}{sup 2} {ge} 3{sigma}(F{sub {degree}}{sup 2})); 3, C{sub 26}H{sub 24}HgAu{sub 2}Cl{sub 4}S{sub 2}P{sub 2}{center dot}CH{sub 2}Cl{sub 2}, space group P{bar 1}, a = 10.199 (6) {angstrom}, b = 12.340 (3) {angstrom}, c = 15.064 (4) {angstrom}, {alpha} = 74.17 (2){degree}, {beta} = 82.76 (3){degree}, V = 1,799 (1) {angstrom}{sup 3}, Z = 2, R = 0.0505 and R{sub w} = 0.0501 for refinement of 178 least-squares parameters with 1,680 reflections (F{sub 0}{sup 2} {ge} 3{sigma}(F{sub 0}{sup 2})).« less
  • A series of vanadium selenites covalently bonded with metal-organic complex, namely, Ni(2,2-bipy){sub 2}V{sub 2}O{sub 4}(SeO{sub 3}){sub 2} (1), Cu(2,2-bipy)V{sub 2}O{sub 4}(SeO{sub 3}){sub 2}·0.5H{sub 2}O (2) and Cu{sub 2}(2,2-bipy){sub 2}V{sub 5}O{sub 12}(SeO{sub 3}){sub 2} (3) (2,2-bipy=2,2-bipyridine) have been hydrothermally synthesized and structurally characterized. They exhibit three different structural dimensions, from 0D cluster, 1D chain to 2D layer. Compound 1 features a 0D {Ni(2,2-bipy)_2V_2O_4(SeO_3)_2}{sub 2} dimeric cluster composed of two {Ni(2,2-bipy)_2}{sup 2+} moieties connected by the {V_4O_8(SeO_3)_4}{sup 4-} cluster. Compound 2 shows a 1D {Cu(2,2-bipy)V_2O_4(SeO_3)_2}{sub n} chain in which the {Cu_2(2,2-bipy)_2}{sup 4+} moieties are bridged by the {V_4O_8(SeO_3)_4}{sup 4−} clusters. Compound 3more » displays a 2D structure consisted of mixed valence vanadium selenites layers {V"I"VV"V_4Se"I"V_2O_1_8}{sub n}{sup 4−} and {Cu(2,2-bipy)}{sup 2+} complex moieties. The adjacent layers are further interconnected via π-π interactions between the 2,2-bipy ligands exhibiting an interesting 3D supramolecular architecture. Both compound 1 and 2 contain a new {V_4O_8(SeO_3)_4}{sup 4−} cluster and compound 3 exhibits the first 2D vanadate polyhedral layer in vanadium selenites/tellurites with organic moieties. - Graphical abstract: We got three new vanadium selenites with organically linked copper/nickel complex, namely, Ni(2,2-bipy){sub 2}V{sub 2}O{sub 4}(SeO{sub 3}){sub 2} (1), Cu(2,2-bipy)V{sub 2}O{sub 4}(SeO{sub 3}){sub 2}·0.5H{sub 2}O (2) and Cu{sub 2}(2,2-bipy){sub 2}V{sub 5}O{sub 12}(SeO{sub 3}){sub 2} (3) by hydrothermally syntheses. They display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. Display Omitted - Highlights: • Three new compounds display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. • The Tetranuclear {V_4O_8(SeO_3)_4}{sup 4−} cluster and the vanadate {V_5O_1_7}{sub n} 2D layer are observed firstly. • Optical Properties and Magnetic Properties of three compounds are reported.« less
  • Two new oxynitride double perovskites of composition Sr{sub 2}FeMoO{sub 6-x}N{sub x} (x=0.3, 1.0) have been synthesized by annealing precursor powders obtained by citrate techniques in flowing ammonia at 750 Degree-Sign C and 650 Degree-Sign C, respectively. The polycrystalline samples have been characterized by chemical analysis, x-ray and neutron diffraction (NPD), Moessbauer spectroscopy and magnetic measurements. They exhibit a tetragonal structure with a=5.5959(1) A, c=7.9024(2) A, V=247.46(2) A{sup 3} for Sr{sub 2}FeMoO{sub 5.7}N{sub 0.3}; and a=5.6202(2) A, c=7.9102(4) A, V=249.85(2) A{sup 3} for Sr{sub 2}FeMoO{sub 5}N; space group I4/m, Z=2. The nitridation process seems to extraordinarily improve the long-range Fe/Mo ordering,more » achieving 95% at moderate temperatures of 750 Degree-Sign C. The analysis of high resolution NPD data, based on the contrast existing between the scattering lengths of O and N, shows that both atoms are located at (O,N)2 anion substructure corresponding to the basal ab plane of the perovskite structure, whereas the O1 site is fully occupied by oxygen atoms. The evolution of the Left-Pointing-Angle-Bracket Fe-O Right-Pointing-Angle-Bracket and Left-Pointing-Angle-Bracket Mo-O Right-Pointing-Angle-Bracket distances suggests a shift towards a configuration close to Fe{sup 4+}(3d{sup 4}, S=2):Mo{sup 5+}(4d{sup 1}, S=1/2). The magnetic susceptibility shows a ferrimagnetic transition with a reduced saturation magnetization compared to Sr{sub 2}FeMoO{sub 6}, due to the different nature of the magnetic double exchange interactions through Fe-N-Mo-N-Fe paths in contrast to the stronger Fe-O-Mo-O-Fe interactions. Also, the effect observed by low-temperature NPD seems to reduce the ordered Fe moments and enhance the Mo moments, in agreement with the evolution of the oxidation states, thus decreasing the saturation magnetization. - Graphical Abstract: We have synthesized and studied the new oxinitride double perovskites Sr{sub 2}FeMoO{sub 6-x}N{sub x}. They present anionic ordering between O and N. The nitridation process improves the long-range Fe/Mo ordering. They show a ferrimagnetic transition with a reduced saturation magnetization compared to Sr{sub 2}FeMoO{sub 6}, due to the different nature of the double exchange interactions through Fe-N-Mo-N-Fe in contrast to Fe-O-Mo-O-Fe. We suggest a shift towards a configuration Fe{sup 4+}(3d{sup 4}, S=2):Mo{sup 5+}(4d{sup 1}, S=1/2). Highlights: Black-Right-Pointing-Pointer Synthesis and study of the new oxinitride double perovskites Sr{sub 2}FeMoO{sub 6-x}N{sub x} (x=0.3, 1.0). Black-Right-Pointing-Pointer Compounds present anionic ordering between O and N. Black-Right-Pointing-Pointer Nitridation process extraordinarily improves the long-range Fe/Mo ordering. Black-Right-Pointing-Pointer We suggest a shift towards a configuration Fe{sup 4+}(3d{sup 4}, S=2):Mo{sup 5+}(4d{sup 1}, S=1/2).« less