The powder method using a powder diffractometer

wastedshadows's version from 2016-01-24 16:55


Powdered minerals contain randomly orientated crystallites. In each powder there will always be some in the correct orientation to diffract waves.


1) The sample powder is suspended on a glass dish and rotated through an angle of θ
2) Monochromatic xrays of a known wave length are fired at the powder
3) An electronic detector that records the intensity of the diffracted angle is rotated through an angle of 2θ
4) Therefore diffraction can only be detected when the lattice plane lies parallel to the surface of the glass.
5) Each peak drawn by the diffractometer represents different diffraction from different lattice planes
6) The 2θ angles recorded by the detector can be used to calculate the d spacing of the crystal using Bragg's law


2θ/2 = θ
2d= n^/Sinθ
d = (n^/Sinθ)/2