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Title: The Pr{sub 2}Se{sub 3}-PrSe{sub 2} system: Studies of the phase relationships and the modulated crystal structure of PrSe{sub 1.85}

Abstract

Thermochemical investigations have been carried out to elucidate the phase relationships in the system Pr{sub 2}Se{sub 3}-PrSe{sub 2} and to construct the p{sub Se}-T-x diagram. The result of the tensimetric and thermogravimetric studies showed the thermal decomposition of PrSe{sub 2} to be a step-wise process due to the formation of a sequence of discrete intermediate phases with the compositions PrSe{sub 1.9}, PrSe{sub 1.85}, PrSe{sub 1.8}, and Pr{sub 2}Se{sub 3}. PrSe{sub 1.85} and PrSe{sub 1.8} have been previously considered as selenium-deficient non-stoichiometric phases. Conclusions derived from the thermodynamic study were verified by X-ray diffraction and electron microscopy studies on single crystals of PrSe{sub 1.85} which were obtained from reactions of praseodymium and selenium in stoichiometric amounts in a KCl flux at 1070K. A two-dimensional modulation could be observed for PrSe{sub 1.85} in X-ray and high-resolution transmission electron microscopy. The structure of PrSe{sub 1.85} was solved and refined in superspace group P4/n({alpha}{beta}12)({beta}-{alpha}12)00 with lattice parameters of a=4.137(1)A, c=8.398(2)A of the basic unit cell and {alpha}={beta}=0.293(1). The origin of the modulation can be attributed to a site occupancy wave and a charge density wave in its planar selenium layer. The experimentally determined magnetic moments indicate Pr{sup 3+} for the polyselenides PrSe{sub 2}, PrSe{submore » 1.9} and PrSe{sub 1.85}.« less

Authors:
 [1];  [2];  [2];  [3];  [4];  [4]
  1. Inorganic Chemistry, Dresden University of Technology, Helmholtzstr. 10, 01069 Dresden (Germany), E-mail: thomas.doert@chemie.tu-dresden.de
  2. Inorganic Chemistry, Dresden University of Technology, Helmholtzstr. 10, 01069 Dresden (Germany)
  3. A. V. Nikolaev Institute of Inorganic Chemistry, Russian Academy of Sciences, Siberian Branch, Acad. Lavrentiev Ave. 3, Novosibirsk, 630090 (Russian Federation)
  4. Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden (Germany)
Publication Date:
OSTI Identifier:
21015676
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 2; Other Information: DOI: 10.1016/j.jssc.2006.10.030; PII: S0022-4596(06)00581-0; Copyright (c) 2006 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; CHARGE DENSITY; DIAGRAMS; LATTICE PARAMETERS; LAYERS; MAGNETIC MOMENTS; MONOCRYSTALS; PHASE STUDIES; POTASSIUM CHLORIDES; PRASEODYMIUM IONS; PRASEODYMIUM SELENIDES; PYROLYSIS; TEMPERATURE RANGE 1000-4000 K; TETRAGONAL LATTICES; THERMAL GRAVIMETRIC ANALYSIS; TRANSMISSION ELECTRON MICROSCOPY; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Doert, Thomas, Graf, Christian, Schmidt, Peer, Vasilieva, Inga G., Simon, Paul, and Carrillo-Cabrera, Wilder. The Pr{sub 2}Se{sub 3}-PrSe{sub 2} system: Studies of the phase relationships and the modulated crystal structure of PrSe{sub 1.85}. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.10.030.
Doert, Thomas, Graf, Christian, Schmidt, Peer, Vasilieva, Inga G., Simon, Paul, & Carrillo-Cabrera, Wilder. The Pr{sub 2}Se{sub 3}-PrSe{sub 2} system: Studies of the phase relationships and the modulated crystal structure of PrSe{sub 1.85}. United States. doi:10.1016/j.jssc.2006.10.030.
Doert, Thomas, Graf, Christian, Schmidt, Peer, Vasilieva, Inga G., Simon, Paul, and Carrillo-Cabrera, Wilder. Thu . "The Pr{sub 2}Se{sub 3}-PrSe{sub 2} system: Studies of the phase relationships and the modulated crystal structure of PrSe{sub 1.85}". United States. doi:10.1016/j.jssc.2006.10.030.
@article{osti_21015676,
title = {The Pr{sub 2}Se{sub 3}-PrSe{sub 2} system: Studies of the phase relationships and the modulated crystal structure of PrSe{sub 1.85}},
author = {Doert, Thomas and Graf, Christian and Schmidt, Peer and Vasilieva, Inga G. and Simon, Paul and Carrillo-Cabrera, Wilder},
abstractNote = {Thermochemical investigations have been carried out to elucidate the phase relationships in the system Pr{sub 2}Se{sub 3}-PrSe{sub 2} and to construct the p{sub Se}-T-x diagram. The result of the tensimetric and thermogravimetric studies showed the thermal decomposition of PrSe{sub 2} to be a step-wise process due to the formation of a sequence of discrete intermediate phases with the compositions PrSe{sub 1.9}, PrSe{sub 1.85}, PrSe{sub 1.8}, and Pr{sub 2}Se{sub 3}. PrSe{sub 1.85} and PrSe{sub 1.8} have been previously considered as selenium-deficient non-stoichiometric phases. Conclusions derived from the thermodynamic study were verified by X-ray diffraction and electron microscopy studies on single crystals of PrSe{sub 1.85} which were obtained from reactions of praseodymium and selenium in stoichiometric amounts in a KCl flux at 1070K. A two-dimensional modulation could be observed for PrSe{sub 1.85} in X-ray and high-resolution transmission electron microscopy. The structure of PrSe{sub 1.85} was solved and refined in superspace group P4/n({alpha}{beta}12)({beta}-{alpha}12)00 with lattice parameters of a=4.137(1)A, c=8.398(2)A of the basic unit cell and {alpha}={beta}=0.293(1). The origin of the modulation can be attributed to a site occupancy wave and a charge density wave in its planar selenium layer. The experimentally determined magnetic moments indicate Pr{sup 3+} for the polyselenides PrSe{sub 2}, PrSe{sub 1.9} and PrSe{sub 1.85}.},
doi = {10.1016/j.jssc.2006.10.030},
journal = {Journal of Solid State Chemistry},
number = 2,
volume = 180,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}