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Title: Al{sub 15}Ge{sub 4}Ni{sub 3}: A new intergrowth structure with Cu{sub 3}Au- and CaF{sub 2}-type building blocks

The new ternary compound Al{sub 15}Ge{sub 4}Ni{sub 3} (τ{sub 2} in the system Al–Ge–Ni) was synthesized in single crystalline form by a special annealing procedure from samples located in the three phase fields [L+Al+τ{sub 2}] and [L+Ge+τ{sub 2}]. The crystal structure of Al{sub 15}Ge{sub 4}Ni{sub 3} was determined by single-crystal X-ray diffraction. The compound crystallizes in a new structure type in space group I4-bar3m, Pearson Symbol cI88, cubic lattice parameter a=11.405(1) Å. Phase diagram investigations indicate stoichiometric composition without considerable homogeneity range; τ{sub 2} melts peritectically at T=444 °C. The crystal structure of Al{sub 15}Ge{sub 4}Ni{sub 3} shows a unique combination of simple Cu{sub 3}Au- and CaF{sub 2}-type building blocks: a three dimensional network of CaF{sub 2}-type units, formed by Ni and Al atoms, is interspaced by clusters (Al{sub 6}Ge{sub 8}) resembling unit cells of the Cu{sub 3}Au-type. Both structural motifs are connected by Al–Ge bonds. The ground state energy of the compound was obtained by DFT calculations and the densities of states were analyzed in detail. In addition, electron density maps were calculated in four different sections through the unit cell using the full potential linearized augmented plane-wave (FLAPW) method. The bonding situation in Al{sub 15}Ge{sub 4}Ni{sub 3} wasmore » discussed combining results from electronic calculations with the analysis of the coordination of atoms. - Graphical abstract: The new compound Al{sub 15}Ge{sub 4}Ni{sub 3} shows a unique combination of simple Cu{sub 3}Au- and CaF{sub 2}-type building blocks. - Highlights: • The crystal structure of Al{sub 15}Ge{sub 4}Ni{sub 3} (space group I4-bar3m) was determined. • It shows a unique combination of CaF{sub 2}- and Cu{sub 3}Au-type building blocks. • Electronic (DFT) calculations were performed to gain insight to chemical bonding.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [1]
  1. Department of Inorganic Chemistry (Materials Chemistry), University of Vienna, Währinger Straße 42, 1090 Wien (Austria)
  2. Department of Mineralogy and Crystallography, University of Vienna, Althanstraße 14, 1090 Wien (Austria)
  3. Department of Physical Chemistry, University of Vienna, Währinger Straße 42, 1090 Wien (Austria)
Publication Date:
OSTI Identifier:
22475600
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 225; Other Information: Copyright (c) 2015 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:
36 MATERIALS SCIENCE; ALUMINIUM BASE ALLOYS; ANNEALING; CALCIUM FLUORIDES; CHEMICAL BONDS; COPPER BASE ALLOYS; DENSITY OF STATES; ELECTRON DENSITY; ELECTRONIC STRUCTURE; GERMANIUM ALLOYS; GOLD ALLOYS; GROUND STATES; INTERMETALLIC COMPOUNDS; LATTICE PARAMETERS; MONOCRYSTALS; NICKEL ALLOYS; PHASE DIAGRAMS; THREE-DIMENSIONAL LATTICES; WAVE PROPAGATION; X-RAY DIFFRACTION