Silver behenate is a silver salt of the long-chain fatty acid behenic acid. It is a possible low-angle diffraction standard that was characterized using the powder diffraction technique. Diffraction patterns obtained with 1.54 Å synchrotron and Cu Ka radiations showed thirteen reflections in the range 1.5-20.0 ° 2-theta.
Description
With the National Institute of Standards and Technology's standard reference material silicon as an internal standard, the long spacing of silver behenate was accurately determined from the profile-fitted synchrotron diffraction peaks, with d001 = 58.380 (3) Ã… (5.8380(3) nm). This result was in agreement with that obtained from the Cu Ka pattern. The profile widths of the silver behenate peaks were found to be consistently larger than those of the silicon peaks, indicating significant line broadening for silver behenate. The average crystallite size along the long-spacing direction of silver behenate was estimated using the Scherrer equation, giving D(avg) = 900 (50) Ã… (85â€"95 nm).
Because silver behenate has a large number of well defined diffraction peaks in the 1.5-20.0° 2-theta range, it is suitable for use as an angle-calibration standard for low-angle diffraction. However, care must be taken if silver behenate is to be used as a peak-profile calibration standard because of line broadening.
References
- T.N. Blanton, T.C. Huang, H. Toraya, C.R. Hubbard, S.B. Robie, D. Louer, H.E. Gobel, G. Will, R. Gilles and T. Raftery (1995). "JCPDS - International Centre for Diffraction Data round robin study of silver behenate. A possible low-angle X-ray diffraction calibration standard". Powder Diffraction 10: 91â€"95.Â
- T.N. Blanton, C.L. Barnes and M. Lelental (2000). "Preparation of silver behenate coatings to provide low- to mid-angle diffraction calibration". J. Appl Cryst 33: 172â€"173. doi:10.1107/S0021889899012388.Â
- Matthews et al. (1950). Analyitical Chemistry 22: 514.Â
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