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. Author manuscript; available in PMC: 2016 Dec 21.
Published in final edited form as: Chem Res Toxicol. 2015 Dec 1;28(12):2313–2324. doi: 10.1021/acs.chemrestox.5b00323

Table 3.

Structural parameters obtained from least-squares curve-fitting of k3-weighted Pb LIII-edge EXAFS spectra of aqueous Pb(II) N-acetylcysteine solutions (see Figure 6).a

Solution Assumed Coordination Scattering Path N R (Å) σ2 (Å2)
A* PbS3 Pb-S 3.0 2.66 0.0108
PbS2S′ Pb b Pb-S 2f 2.65 0.0075
Pb-S′ 1f 2.77 0.0086
Pb … Pb 1f 3.76 0.0208
B* PbS3 Pb-S 3.5 2.65 0.0069
C* PbS3 Pb-S 3.8 2.65 0.0068
D* PbS3 Pb-S 3.8 2.65 0.0066
E* PbS3 Pb-S 3.8 2.65 0.0065
A PbS3 Pb-S 2.9 2.65 0.0107
PbS2S′ Pb b Pb-S 2f 2.64 0.0073
Pb-S′ 1f 2.78 0.0101
Pb … Pb 1f 3.66 0.0284
B PbS3 Pb-S 3.1 2.65 0.0081
C PbS3 Pb-S 3.5 2.65 0.0068
D PbS3 Pb-S 3.7 2.65 0.0068
E PbS3 Pb-S 3.6 2.64 0.0064
a

S02 = 0.9 fixed; f = fixed; fitting k-range ~ 2.8 – 12.5 Å−1 (solutions A*, A – E) and ~ 3.0 – 13.7 Å−1 (solutions B* – E*). Estimated error limits for R is ± 0.04 Å and for σ2 ± 0.002 Å2; refined N accuracy within ± 20 %.

b

Selected model shown in Figure 6; the fitting residual improved from 27.3 (PbS3) to 26.9 (PbS2S′ Pb) for solution A, and from 20.7 to 19.0 for solution A*.