کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1625365 | 1516428 | 2008 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Novel intermetallics with the Ca11 Ga7 structure type
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
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چکیده انگلیسی
The binary alkaline earth (AII) trielides Ca11 Ga7 and Sr11 In7 crystallize with a singular structure type (cubic, space group Fm3¯m, aâ1600 (AII=Ca) and 1700 (AII=Sr)âpm, Z=8). Fourteen new ternary Ca and Sr mixed trielides and triel/tetrelides forming this structure type were synthesized from stoichiometric mixtures of the elements and characterized by single crystal X-ray diffraction. The structures exhibit isolated M(1) atoms (M(2)=Al, Ga, In, Sn, Pb) together with tetrahedral units [M(1)4], which are formed by the triel elements exclusively. Remarkably, one of the four crystallographically independent AII positions is - as in the pure element - coordinated by AII partners in a cuboctahedral arrangement. In the mixed MIII /MIV compounds, a maximum phase range up to a maximum composition limit of A11[M(1)4III][M(2)IV]3 is observed, which nearly corresponds to an ionic description according to the Zintl concept (tetrahedral anions [M4III]8â isoelectronic to white phosphorus P4 besides isolated noble gas isosteric tetrelide anions [MIV]4â). In the case of the Sr/In/Pb and some Ca compounds, the A position that is coordinated by alkaline earth atoms only is statistically substituted by the heavier triel/tetrel element. The stabilities and phase ranges of the compounds, which are influenced by geometric and electronic factors (investigated by FP-LAPW band structure calculations), are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 448, Issues 1â2, 10 January 2008, Pages 128-140
Journal: Journal of Alloys and Compounds - Volume 448, Issues 1â2, 10 January 2008, Pages 128-140
نویسندگان
Marco Wendorff, Caroline Röhr,