²⁰⁷Pb NMR Chemical-Shift Tensors of the Lead (II) Halides and the Lead (II) Hydroxyhalides

Abstract

The NMR properties of the solid lead (II) halides and the lead (II) hydroxyhalides are reported. The analysis shows extremely wide powder patterns in all cases except the lead (II) iodide. The results indicate that one should be able to distinguish the lead (II) halide from the corresponding lead (II) hydroxyhalide in a mixture.

XANES Spectroscopy Study of Pb(Ti, Zr)O3 Ferroelectric Thin Films

“…At the same time, the titanium-rich PZT 30/70 sample do not show similar absorption in the vicinity of 13 021 eV. This fact correlates with the 207 Pb NMR solidstate data of PbTiO 3 [9,10] indicating inactive 6s 2 electron pair, and the 207 Pb NMR solid-state spectra of PbZrO 3 (Fig. 6), showing the superposition of two lines which may be connected with activation of 6s 2 electron pair in this case.…”

Lead‐207 NMR spectroscopy at 1.4 T: Application of benchtop instrumentation to a challenging I = ½ nucleus

“…Figure 6a illustrates the 207 Pb NMR spectrum of PbCl 2 acquired at 1.4 T. The chemical shift, δ iso = −1,745 ± 6 ppm, is slightly lower than the value of −1,721 ± 2 ppm reported by Dmitrenko et al [ 31 ] ; a similar value was reported by Dybowski et al [ 32 ] Table 1 summarizes the chemical shift tensor principal components obtained by us and by Dmitrenko et al [ 31 ] As for the 207 Pb spectra for Pb(NO 3 ) 2 discussed above, the distinct features arising from anisotropic magnetic shielding in PbCl 2 are not as clearly defined but still measurable at 1.4 T. Each 207 Pb nucleus in PbCl 2 is coordinated to nine 35 Cl or 37 Cl nuclei (both I = 3/2, with NAs of 75.78% and 24.22%, respectively) with six distinct Pb‐Cl bond lengths. [ 33 ] Thus, a given 207 Pb nucleus is susceptible to broadening due to dipolar and J spin‐spin coupling from both 35 Cl and 37 Cl nuclei from a total of nine chlorine sites with six distinct environments; because these interactions are invariant to field strength, the apparent broadening, on the ppm scale, is greater at lower fields (see below).…”

“…Table 1 summarizes the chemical shift tensor parameters obtained from simulations of the data; values are similar. Figure 6a illustrates the 207 Pb NMR spectrum of PbCl 2 acquired at 1.4 T. The chemical shift, δ iso = −1,745 ± 6 ppm, is slightly lower than the value of −1,721 ± 2 ppm reported by Dmitrenko et al [31] ; a similar value was reported by Dybowski et al [32] Table 1 summarizes the chemical shift tensor principal components obtained by us and by Dmitrenko et al [31] As for the 207 Pb spectra for Pb(NO 3 ) 2 discussed above, the distinct features arising from anisotropic magnetic shielding in PbCl 2 are not as clearly defined but still measurable at 1. 4…”

Scalar and spin-dependent relativistic effects on magnetic properties calculated with four-component methods: the nuclear magnetic resonance parameters of the lead halides

“…Furthermore, an inspection of the tensor components of the relativistic σ p and σ d shows that, to a large extent, σ d is almost isotropic, reflecting its deep core origin, while the different components of the tensor σ p behave distinctly in response to the kinematic effects of relativity, σ p ⊥ being more sensitive than σ p z , and this, at its turn, more sensitive than σ p , yielding σ p ⊥ < σ p z < σ p in all cases, both relativistically and nonrelativistically. It has been noted that the measured 207 Pb isotropic shifts in the lead dihalides fit to a linear correlation with the inverse of the ionization potential [14]; such a correlation has been taken as an indication that the paramagnetic contribution to the chemical shift is dominant. Reciprocally, given that in our calculations the paramagnetic contributions are the most affected by relativistic effects, and taking the HOMO-LUMO gap as a measure of the ionization potential, Figure 1 shows that there is a linear correlation between each tensor component of the relativistically calculated σ p (Pb) with the inverse of ε HOMO−LUMO .…”

“…It was shown that molten PbF 2 vaporizes partly as molecular PbF 2 with a considerable desproportionation [13]. Measurements of 207 Pb chemical shifts in lead halide powders have been performed using the magic-angle spinning (MAS) technique [14]. Calculations of 19 F NMR shielding constants has been reported for a number of metal fluorides, including PbF 2 [15].…”