Table 1.

d-spacing of analyzed Pb nanospheres compared with published values for native Pb, Pb–oxides, and Pb–silicates

dhkl observed, ÅPb cubicPbO2 orthorhombicPbO orthorhombicPb3O4 tetragonalPb3Si2O7 trigonalPb21(Si7O22)2Si4O13 hexagonal
*a0 = 4.97 Åa0 = 4.9505 Åa0 = 4.9858 Åa0 = 5.8952 Åa0 = 8.8118 Åa0 = 10.1264 Åa0 = 9.9244 Å
b0 = 5.9590 Åb0 = 5.4930 Åb0 = 8.8118 Åb0 = 10.1264 Åb0 = 9.9244 Å
c0 = 5.4626 Åc0 = 4.7544 Åc0 = 6.5639 Åc0 = 38.6780 Åc0 = 34.2357 Å
2.9795 (020)2.9476 (200)2.9034 (112)2.9230 (300)3.0371 (124)
2.83 n = 7 (SD = 0.03)2.858 (111)2.8649 (300)
2.7310 (002)2.7465 (020)2.7863 (310)
2.4929 (200)2.4896 (120)2.5216 (212)
2.44 n = 12 (SD = 0.07)2.475 (020)2.3952 (102)2.3782 (021)2.4437 (230)2.4842 (223)2.4746 (221)
2.0883 (041)
2.1196 (211)2.0768 (330)
1.99 n = 5 (SD = 0.09)2.021 (211)2.0132 (022)2.0460 (112)2.0320 (411)2.009 (321)
1.75 n = 6 (SD = 0.01)1.750 (022)1.7591 (212)1.7974 (022)1.7907 (412)
1.52 n = 11.565 (113)1.5290 (132)1.5146 (302)1.5111 (350)1.4407 (431)
  • An asterisk indicates calculation from d-spacing. n, number of measurements; SD, standard deviation of measurements. From all measurements, only five different sets of d-spacings were obtained (first column), and these indicate cubic crystallographic symmetry. In all other crystal structures for Pb–oxide and Pb–silicate, d-spacings much larger than 2.83 Å should be observed. Nanospheres shown in Fig. 2 E and F can be only indexed as cubic Pb.