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
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
Novel intermetallics with the Ca11 Ga7 structure type
چکیده انگلیسی
The binary alkaline earth (AII) trielides Ca11 Ga7 and Sr11 In7 crystallize with a singular structure type (cubic, space group Fm3¯m, a≈1600 (AII=Ca) and 1700 (AII=Sr) pm, 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]8− isoelectronic to white phosphorus P4 besides isolated noble gas isosteric tetrelide anions [MIV]4−). 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 1–2, 10 January 2008, Pages 128-140
نویسندگان
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