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45 Sc Solid State NMR Spectroscopy – A Complementary Tool to X‐ray Crystallography for Structure Determination of Intermetallic Compounds
Author(s) -
Eckert Hellmut,
Pöttgen Rainer
Publication year - 2010
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.201000197
Subject(s) - scandium , solid state nuclear magnetic resonance , magic angle spinning , nuclear magnetic resonance crystallography , chemistry , intermetallic , quadrupole , spectroscopy , electric field gradient , nuclear magnetic resonance spectroscopy , carbon 13 nmr satellite , crystallography , materials science , fluorine 19 nmr , nuclear magnetic resonance , atomic physics , physics , stereochemistry , organic chemistry , alloy , quantum mechanics
45 Sc solid state NMR spectroscopy is a useful complementary tool to X‐ray crystallography for structure determination. Recent developments in the field of intermetallic scandium compounds are reviewed. The structural topics concern defect formation, structural disorder, superstructure formation, as well as the detection of multiple scandium sites. To address questions of this kind, high‐resolution 45 Sc NMR spectroscopic techniques were established as a new structural tool for the quantification of the local coordination scandium environments and the detailed characterization of their internal NMR interaction parameters. Owing to the moderately sized nuclear electric quadrupole moment of 45 Sc, the magic‐angle spinning spectra are affected both by first‐ and second‐order quadrupolar perturbations, which can be analyzed and quantified by fast magic angle spinning, assisted by lineshape simulations. The resolution can be further improved by correlating triple quantum (TQ) with single quantum coherences. Using this 2D NMR spectroscopic methodology, the effects of magnetic shielding and second‐order quadrupolar perturbations on the MAS NMR lineshape can be separated, enabling a more precise experimental characterization of electric field gradients present at the 45 Sc nuclei. Structure validation includes the precise measurement of these parameters and comparison with quantum mechanically calculated values based on the atomic positions. In this regard, satisfactory results were obtained using the WIEN2k program.