Powder X-ray Diffraction (XRD) is one of the primary techniques used by mineralogists and solid state chemists to examine the physico-chemical make-up of unknown solids. This data is represented in a collection of single-phase X-ray powder diffraction patterns for the three most intense D values in the form of tables of interplanar spacings (D), relative intensities (I/Io), and mineral name.
The XRD technique takes a sample of the material and places a powdered sample in a holder, then the sample is illuminated with x-rays of a fixed wave-length and the intensity of the reflected radiation is recorded using a goniometer. This data is then analyzed for the reflection angle to calculate the inter-atomic spacing (D value in Angstrom units - 10-8 cm). The intensity(I) is measured to discriminate (using I ratios) the various D spacings and the results are to identify possible matches.
Example Subject Searches
Example: intensity-o1.76* finds all minerals with the most intense d-spacing of 1.76 to 1.7699 angstroms
Example: "intensity-o-2.5*" "2.9*" "3.99*" finds all minerals that have d-spacings starting at 2.5 to 2.5999 angstroms with data at 2.9 to 2.999 and 3.99 to 3.999 angstroms, index of refraction, % element, etc.
Internet course at Birkbeck College
Table of X-Ray Diffraction Values In the Mineralogy Database
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