The effects of crystal size distributions on the crystallinity analysis of bone mineral.

The mechanisms by which crystal size distributions affect the usual method of quantities X-ray diffraction analysis of bone mineral have been determined on synthetic crystals. It was observed that each component of a crystal-size distribution diffracts independently. This independence causes systematic nonlinear behavior in the plot of integrated intensity vs. broadening parameter curves. The nonlinearity resulted in an overestimation of the amount of nondiffracting material present in bone mineral. Because crystal size distributions may vary for different crystallographic directions, it is strongly suggested that the usual practice of adding the c-axis and a-axis integrated intensities to estimate the crystallinity of the sample be discontinued. Methods of understanding the crystal size distribution function in bone mineral are discussed and evaluated.