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Title: Structure, thermodynamic, and magnetic properties of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, and Gd

Abstract

The structure of Nd{sub 4}PdO{sub 7} has been determined and refined using the Rietveld method and combined CuK{alpha}{sub 1} X-ray and neutron powder data in space group P{bar 1} with unit cell a = 15.972(2), b = 7.1927(7), c = 6.9160(6) {angstrom}, {alpha} = 96.299(4), {beta} = 131.643(3), {gamma} = 121.438(3){degree}, V = 353.83(6) {angstrom}{sup 3} and Z = 2, to R{sub F} = 2.0% (neutron data) and R{sub F} = 6.2% (X-ray data). The structure is closely related to the monoclinic La{sub 4}PdO{sub 7} structure and exhibits Nd atoms coordinated by seven O atoms and Pd atoms coordinated by a square of O atoms. Isolated chains of trans-corner-sharing PdO{sub 4} squares are straight in the La{sub 4}PdO{sub 7} structure and staggered in the Nd{sub 4}PdO{sub 7} structure. Electron and X-ray powder diffraction data show that Ln{sub 4}PdO{sub 7} with Ln = Sm, Eu, and Gd is isostructural with Nd{sub 4}PdO{sub 7}. The enthalpies of dissolution of Ln{sub 4}PdO{sub 7} (Ln = La, Nd) in 1.000 M HCl have been measured with an in-house built calorimeter, and from these values the enthalpies of formation for the compounds have been calculated. The decomposition temperatures of Ln{sub 4}PdO{sub 7} with Ln =more » La and Nd in oxygen have been determined by thermogravimetric measurements and found to decrease from 1645 {+-} 10 K for La{sub 4}PdO{sub 7} to 1540 {+-} 10 K for Nd{sub 4}PdO{sub 7}. Using these data, an Ellingham diagram has been constructed assuming temperature-independent {Delta}H{sub f}{degree} and {Delta}S{sub f}{degree}. The magnetic susceptibilities of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, Gd, recorded in the temperature range 10--320 K, were found to be in agreement with the expected ones for noninteracting Ln{sup 3+} ions.« less

Authors:
; ;  [1]
  1. Stockholm Univ. (Sweden)
Publication Date:
OSTI Identifier:
696676
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 146; Journal Issue: 2; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL STRUCTURE; THERMODYNAMIC PROPERTIES; MAGNETIC PROPERTIES; RARE EARTH COMPOUNDS; OXIDES; PALLADIUM OXIDES; X-RAY DIFFRACTION; NEUTRON DIFFRACTION; LATTICE PARAMETERS; CALORIMETRY; EXPERIMENTAL DATA

Citation Formats

Andersson, M., Grins, J., and Nygren, M. Structure, thermodynamic, and magnetic properties of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, and Gd. United States: N. p., 1999. Web. doi:10.1006/jssc.1999.8387.
Andersson, M., Grins, J., & Nygren, M. Structure, thermodynamic, and magnetic properties of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, and Gd. United States. doi:10.1006/jssc.1999.8387.
Andersson, M., Grins, J., and Nygren, M. Wed . "Structure, thermodynamic, and magnetic properties of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, and Gd". United States. doi:10.1006/jssc.1999.8387.
@article{osti_696676,
title = {Structure, thermodynamic, and magnetic properties of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, and Gd},
author = {Andersson, M. and Grins, J. and Nygren, M.},
abstractNote = {The structure of Nd{sub 4}PdO{sub 7} has been determined and refined using the Rietveld method and combined CuK{alpha}{sub 1} X-ray and neutron powder data in space group P{bar 1} with unit cell a = 15.972(2), b = 7.1927(7), c = 6.9160(6) {angstrom}, {alpha} = 96.299(4), {beta} = 131.643(3), {gamma} = 121.438(3){degree}, V = 353.83(6) {angstrom}{sup 3} and Z = 2, to R{sub F} = 2.0% (neutron data) and R{sub F} = 6.2% (X-ray data). The structure is closely related to the monoclinic La{sub 4}PdO{sub 7} structure and exhibits Nd atoms coordinated by seven O atoms and Pd atoms coordinated by a square of O atoms. Isolated chains of trans-corner-sharing PdO{sub 4} squares are straight in the La{sub 4}PdO{sub 7} structure and staggered in the Nd{sub 4}PdO{sub 7} structure. Electron and X-ray powder diffraction data show that Ln{sub 4}PdO{sub 7} with Ln = Sm, Eu, and Gd is isostructural with Nd{sub 4}PdO{sub 7}. The enthalpies of dissolution of Ln{sub 4}PdO{sub 7} (Ln = La, Nd) in 1.000 M HCl have been measured with an in-house built calorimeter, and from these values the enthalpies of formation for the compounds have been calculated. The decomposition temperatures of Ln{sub 4}PdO{sub 7} with Ln = La and Nd in oxygen have been determined by thermogravimetric measurements and found to decrease from 1645 {+-} 10 K for La{sub 4}PdO{sub 7} to 1540 {+-} 10 K for Nd{sub 4}PdO{sub 7}. Using these data, an Ellingham diagram has been constructed assuming temperature-independent {Delta}H{sub f}{degree} and {Delta}S{sub f}{degree}. The magnetic susceptibilities of Ln{sub 4}PdO{sub 7} with Ln = La, Nd, Sm, Eu, Gd, recorded in the temperature range 10--320 K, were found to be in agreement with the expected ones for noninteracting Ln{sup 3+} ions.},
doi = {10.1006/jssc.1999.8387},
journal = {Journal of Solid State Chemistry},
number = 2,
volume = 146,
place = {United States},
year = {1999},
month = {9}
}