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

Journal Article · Fri May 15 00:00:00 EDT 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2014.12.020· OSTI ID:22475600

Reichmann, Thomas L.; Jandl, Isabella ^[1]; Effenberger, Herta S. ^[2]; Herzig, Peter ^[3]

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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)

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} was 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.

• OSTI ID: 22475600
• Journal Information: Journal of Solid State Chemistry, Vol. 225; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

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