Dear Daniel
Have you thought of using other heavy metal soaps?
e.g. Lead or silver stearate. These soaps, if pure, should give
a diffraction pattern which behaves like a transmission grating.
The alkane chain being eqivalent to the distance between slits,
so you can tailor the spacing between the diffraction peaks by
varying the alkane chain. I have tried lead stearate with X-rays
as a powder but I got some unexpected extra diffraction. This
may have been due to impurities. The best way to get good
diffraction from them is to grow the layers on a glass or Quartz
plate. See Adv. in X-ray Anal. vol 25, pp289-294 (1982).
I hope this helps.
Yours
Rory.
