Sprinkling and backpacking may reduce preferred orientation. This also minimized primary and secondary extinction effects. Using a wet grinding method reduces defects. Pick an internal standard that has equant particles and that does not interfere with the peaks of interest. Slurry mounting with acetone can minimized preferred orientation.
Water is a polar compound, where as acetone is less polar and it evaporates quickly.
If particles are kept away from each other while drying, then van der waal forces will not let them to attract to each other and self align. The thickness of the powder should be great enough to prevent the beam from passing through to the substrate below. The mass absorption coefficient of the sample. The previous table gives requisite powder thickness for various materials with small, medium and large mass absorption coefficients and with different porosity. Thickness of the sample.