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.
Search X-Ray Diffraction Table
Users can now search on D1, D2, D3, and
chemical formula in any order from the Table of
X-Ray spacing. The search is based on reported values from each mineral
where a diffraction file has been published. Two theta values can be calculated
for different wavelengths based on commonly used X-Ray anode values. In
addition, the user can input any value for X-Ray wavelength and the 2 theta
angles are calculated for that wavelength.
1. Minmax tolerance is % so that all D values with a +/- range in percent are
returned. The default is 10%.
2. The wild card character for formula searches is "%" and is
required, the search is case sensitive, and the order is important. For
example, %K%Na% will give different results than %Na%K% depending
on the order the element occurs in the formula.
3. You can use any combination of D1, D2, D3 and formula.
4. Try increasing the tolerance. The larger the tolerance, the more records are
5. Don't get too involved with complicated formula searches, one or two elements
Don't forget the % wild card in the search.
Other References to X-Ray Diffraction
Search the Mineralogy Database
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.