Temperature dependence of the nuclear quadrupole frequencies of 23Na and 187Re in NaReO4

Intercalation Route to Complex Perovskites AM0.2Ta0.8O2.8N0.2 (A = Sr, Ba; M = Li, Na): Neutron Diffraction and Nuclear Magnetic Resonance Study

“…The ternary oxides, Na 2 WO 4 , NaReO 4 , and NaTaO 3 have a single and well-defined crystallographic site of Na. Accordingly their spectra exhibited typical line shapes stemming from quadrupolar coupling of the spin = 3/2 nucleus 23 Na, in good agreement with previous reports. − The MAS line shapes of reference oxides were fitted using the program DMFIT, from which the 23 Na shift (δ CS ), the quadrupolar coupling constant ( C Q ), and the asymmetry parameter (η) could be determined; δ CS = 4.7 ppm, C Q = 2.43 MHz, η = 0.00 for Na 2 WO 4 , δ CS = −17.6 ppm, C Q = 1.02 MHz, η = 0.0 for NaReO 4 , δ CS = −2.6 ppm, C Q = 1.46 MHz, η = 0.87 for NaTaO 3 (see Supporting Information for fitting profiles). On the other hand, the three complex perovskites showed featureless and roughly symmetrical transition lines, presumably due to the lack of long-range structural order.…”