The Solid Solution Sr(1-x)Ba(x)Ga2: Substitutional Disorder and Chemical Bonding Visited by NMR Spectroscopy and Quantum Mechanical Calculations.
Complete miscibility of the intermetallic phases (IPs) SrGa2 and BaGa2 forming the solid solution Sr(1-x)Ba(x)Ga2 is shown by means of X-ray diffraction, thermoanalytical and metallographic studies. Regarding the distances of Sr/Ba sites versus substitution degree, a model of isolated substitution centres (ISC) for up to 10% cation substitution is explored to study the influence on the Ga bonding situation. A combined application of NMR spectroscopy and quantum mechanical (QM) calculations proves the electric field gradient (EFG) to be a sensitive measure of different bonding situations. The experimental resolution is boosted by orientation-dependent NMR on magnetically aligned powder samples, revealing in first approximation two different Ga species in the ISC regimes. EFG calculations using superlattice structures within periodic boundary conditions are in fair agreement with the NMR spectroscopy data and are discussed in detail regarding their application on disordered IPs.
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany).|Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS), Nöthnitzer Straße 40, 01187 Dresden (Germany).|Present address: University of Cambridge, Department of Chemistry, Lensfield Road CB2 1EW, Cambridge (UK).
Oliver
O
Pecher
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany).
Bernhard
B
Mausolf
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany).
Kevin
K
Lamberts
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany).
Dirk
D
Oligschläger
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany).
Carina
C
Niewieszol
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany).
Ulli
U
Englert
RWTH Aachen University, Institut für Anorganische Chemie (IAC), Landoltweg 1, 52074 Aachen (Germany). frank.haarmann@ac.rwth-aachen.de.
Frank
F
Haarmann
NMR spectroscopy; chemical bonding; intermetallic phases; quantum mechanical calculations; substitutional disorder