Phase Relations and Crystal Structures in the Ternary Systems Sr-{Ag, Au}-{Si, Ge}

Autor(en): Isolde Zeiringer, Andrij Grytsiv, Ernst Bauer, Gerald Giester, Peter Franz Rogl
Abstrakt: Phase equil. in the isothermal sections of the ternary systems Sr-{Ag, Au}-{Si, Ge} were detd. in the (Si) or (Ge) rich part up to 33.3 at % Sr after annealing at 700 °C (Sr-{Ag, Au}-Ge) or 800 °C (Sr-{Ag, Au}-Si). Tentative liquidus projections were constructed for the Si, Ge-rich part of all the four phase diagrams. These systems are characterized by a series of ternary compds., exhibiting in some cases extended homogeneity regions at a const. Sr content. Compds. in the Si, Ge-rich region essentially form along two sections: at 33.3 at % Sr (AlB2-family) and at 20 at % Sr (BaAl4-family of structure types). The crystal structures of the novel equil. phases were derived by X-ray single crystal diffraction: Sr2Ag1+xSi3-x-y$$square$$y [Sr2LiSi3 type; x = 0.17, y = 0.43: a = 8.4488(2), b = 14.6376(2), c = 18.4018(2) Å], SrAg2-xSi2+x [ThCr2Si2 type; x = 0.1: a = 4.37664(6), c = 10.4517(2) Å], Sr(Au1-y$$square$$y)(Si1-xAux)3 [BaNiSn3 type; x = 0.59, y = 0.64: a = 4.4594(2), c = 10.1013(6) Å] and SrAu5-x$$square$$xSi2 [BaAu5Si2 type; x = 0.7: a = 8.7557(3), b = 6.9945(2), c = 9.8873(3) Å]. The crystal structures of Sr(AgxGe1-x)2 [AlB2 type; x = 0.25: a = 4.3431(2), c = 4.5938(1) Å], SrAg2-xGe2+x [ThCr2Si2 type; x = 0.2: a = 4.4476(2), c = 10.822(1) Å] and Sr(AuxGe1-x)2 [AlB2 type; x = 0.25: a = 4.3263(2), c = 4.5852(7) Å] were evaluated by X-ray powder Rietveld anal. Compn. dependent polymorphism was obsd. among the BaAl4-type deriv. structures for SrAu2-xGe2+x: CaBe2Ge2 type [x = 0.45: a = 4.4796(2), c = 10.6315(5) Å], BaCu2Sb2 type [x = 0.35: a = 4.4866(2), c = 31.808(1) Å] and ThCr2Si2 type [x = 0.2: a = 4.5214(4), c = 10.336(1) Å]. Similarly, Sr(AuxSi1-x)2 exhibits the Ca2AgSi3 structure type [x = 0.25: a = 8.3407(2), b = 14.4465(2) and c = 9.2664(3) Å] and the AlB2 type [x = 0.375: a = 4.2241(2), c = 4.5799(3) Å]. The structural chem. of the BaAl4 deriv. structures within the sections SrT2-xX2+x is discussed.
Organisation(en): Institut für Physikalische Chemie, Institut für Mineralogie und Kristallographie
Externe Organisation(en): Christian Doppler Forschungsgesellschaft, Technische Universität Wien
Journal: Zeitschrift für Anorganische und Allgemeine Chemie
Band: 641
Seiten: 1404-1421
Anzahl der Seiten: 18
ISSN: 0044-2313
DOI: https://doi.org/10.1002/zaac.201500045
Publikationsdatum: 03-2015
Peer-reviewed: Ja
ÖFOS 2012: 104003 Anorganische Chemie, 104017 Physikalische Chemie, 104011 Materialchemie, 105113 Kristallographie
Schlagwörter
ASJC Scopus Sachgebiete: Inorganic Chemistry
Link zum Portal: https://ucrisportal.univie.ac.at/de/publications/phase-relations-and-crystal-structures-in-the-ternary-systems-srag-ausi-ge(a54e530e-c23b-4d44-9686-8951e38e1ddf).html

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