Premium
On Ternary Intermetallic Aurides: CaAu 2 Al 2 , SrAu 2– x Al 2+ x and Ba 3 Au 5+ x Al 6– x
Author(s) -
Stegemann Frank,
Benndorf Christopher,
Zhang Yuemei,
Bartsch Manfred,
Zacharias Helmut,
Fokwa Boniface P. T.,
Eckert Hellmut,
Janka Oliver
Publication year - 2017
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700103
Subject(s) - intermetallic , orthorhombic crystal system , crystallography , monoclinic crystal system , crystal structure , ternary operation , materials science , x ray photoelectron spectroscopy , solid solution , powder diffraction , tantalum , chemistry , nuclear magnetic resonance , metallurgy , physics , alloy , computer science , programming language
The intermetallic compound CaAu 2 Al 2 , and the members of the solid solutions SrAu 2– x Al 2+ x (0 ≤ x ≤ 0.33) and Ba 3 Au 5+ x Al 6– x ( x = 0, 0.14, 0.49) were synthesized from the elements in sealed tantalum ampoules. The Ca compound crystallizes with the orthorhombic ThRu 2 P 2 type structure, whereas the targeted SrAu 2 Al 2 was found to form a solid solution according to SrAu 2– x Al 2+ x . For the Ba system no “BaAu 2 Al 2 ” was found, however, Ba 3 Au 5+ x Al 6– x was discovered to crystallize in the monoclinic space group C 2/ c with its own structure type. The samples were investigated by powder X‐ray diffraction and their crystal structures were refined on the basis of single‐crystal X‐ray diffraction data. All compounds were characterized furthermore by susceptibility measurements. The crystallographic aluminum sites of CaAu 2 Al 2 and Ba 3 Au 5 Al 6 can be differentiated by 27 Al solid state NMR spectra on the basis of their different electric field gradients, in agreement with theoretical calculations. The electron transfer from the alkaline earth metals and the aluminum atoms onto the gold atoms was investigated by X‐ray photoelectron spectroscopy (XPS) classifying these intermetallics as aurides, in full agreement with the calculated Bader charges.