Observation of 91Zr NMR in zirconium-based metals and oxides

Multinuclear NMR study of silica fiberglass modified with zirconia

“…Solid-state NMR is a well-established tool in studying the structure of glass and other disordered phases. This is especially applicable to silica-based glasses where all the atomic constituents possess NMR-active nuclei ( 1 H, 17 O, 23 Na, 27 Al, 29 Si, 91 Zr). For each such NMR-active atom under investigation it is possible to analyze both short (1.5-3.0Å, Si-O, Na-O) and medium range order (3.0-10.0Å, Si-Si, Si-Na, Na-Na).…”

“…23 Na NMR spectra were referenced to external 0.1 M NaCl/H 2 O. 29 Si MAS NMR spectra were recorded at 79.5 MHz using a single-pulse sequence with 10 ms rf pulse (p/2). The relaxation delay of 20 s was found sufficient for complete relaxation.…”

“…

H NMR 23 Na NMR 29 Si NMR 91 Zr NMR Fiberglass Silica Zirconia a b s t r a c t Silica fiberglass textiles are emerging as uniquely suited supports in catalysis, which offer unprecedented flexibility in designing advanced catalytic systems for chemical and auto industries. During manufacturing fiberglass materials are often modified with additives of various nature to improve glass properties.

…”

Ist 91Zr-Festkörper-Kernresonanzspektroskopie praktikabel?

“…B. Zirkonium oxidkeramiken und zirkoniumdotierte Phosphatglas keramiken haben in den letzten Jahren stark an Be deutung gewonnen. Während die hochauflösende Kernresonanzspektroskopie an "gebräuchlichen" Ker nen (*H, ÜB, 13C, 31P, 27AI, 29Si) seit Jahren erfolg reich zur Strukturaufklärung im Festkörper ange wandt wird, sind NMR-Untersuchungen am Zirkonium-91-Kern nur in eng begrenztem Umfang be kannt [1][2][3][4][5]. Die Ursache dafür ist neben der geringen Empfindlichkeit (Häufigkeit des Isotops = 11,23%; re lative Empfindlichkeit = 9,48 • 10"3), vor allem im starken Kernquadrupolmoment des Zirkonium-91-Kerns (-0.21 • 10"28 m2 [6]) zu sehen.…”

On the practical aspects of recording wideline QCPMG NMR spectra

“…Therefore, for patterns with breadths greater than the excitation bandwidth, the full spectrum must be reconstructed from segments acquired at different offset frequencies [4,5,28,49,[76][77][78]. Attempts at overcoming excitation bandwidth limitations for quadrupolar nuclei have recently been reported which include the use of microcoils [79][80][81] or frequency-swept pulses [81][82][83][84].…”