This document discusses several methods for X-ray diffraction analysis of crystal structures, including the Laue method, Bragg spectrometer method, rotating crystal method, and powder crystal method. The methods utilize X-rays generated by a cathode ray tube and directed at a crystal sample to produce a diffraction pattern that can reveal the internal crystal structure. Key steps involve collimating the X-ray beam, positioning the crystal sample, and recording the diffraction pattern on photographic plates or films. Analysis of the diffraction patterns allows identification of crystal structures.

2. These methods are based on the scattering of X rays by crystal. These x-
rays are generated by a cathod ray tube, filtered to produce
monochromatic radiation, collimated to concentrate and directed
towards the sample. By these methods, one can identify the crystal
structures of various solid compounds. These methods are extremely
important as compared with X-Ray absorption and X-Ray flourescence
methods.

3. X-Ray Diffraction methods:-
X-Ray diffraction methods are generally used for the investigating the
internal structures. The following methods are used..
1) Laue photographic method.
2) Bragg X-Ray spectrometer method
3) Rotating crystal method.
4) Powder crystal method.
1) Laue photographic method:-In these method the phenomenon of
crystal by two methods.
 Transmission method
 Back reflection method

4. Transmission methods:-

5.  A is a source of X-Rays. this emits a beam of continuous wavelength,
called as White Radiation obtained from a tungusten target at about
60000 volts.
 B is a pinhole collimator. when x- rays obtained fro A are allowed to
pass through the pinhole collimator, a fine pencil of X-Rays is obtained.
The diameter of pinhole is important for the stand point of detail
diffraction pattern. The smaller is the diameter the sharper is the
interference.
 C is a crystal whose internal structure is to be investigated. The crystal
is set on a holder to adjust its orientation.
 D is a film arranged on a rigid base. The film is provided with beam
stop to prevent direct beam from causing excessive fogging of the fim.

6. Back reflection method:-
This method provides similar information as the transmission
method. The back-reflection method is the only method for the
investigation of large and thick specimens.

7. 2) Bragg X-Ray spectrometer method
 According to Laue,if a beam of X-Rays is passed through a crystal,the
emitted x-rays by the crystal are obtained on a photographic plate.
 Using the photographs,Bragg analysed the structure of crystal of NaCl,
KCl and ZnS.
 Braggs devised a spectrometer to measure the intensity of of X-Ray
beam. The spectra obtained in this way can be employed for
crystallographic analysis.The Braggs eq. is as follows-

8. 3)Rotating Crystal method
 The X-Ray are generated in the x-ray tube and then beam is made
monochromatic by a filter.
 From the filter the beam is then allowed to pass through collimating
system which permits a fine pencil of parallel x-rays.
 From the collimetor, the x-ray beam is made to fall on a crystal
mounted on a shaft which can be rotated at uniform rate bye a small
motor.
 The shaft is moved to put the crystal into slow rotation about a fixed
axis. These causes the sets of planes coming successively into their
reflecting position.
 Each plane will produce a spot on the photographic plate. One can
take a photograph of a diffraction pattern upon a parpedicular to X-
ray beam or upon a film in a cylindrical camera, the axis of which
coincides with the axis of rotation of the crystal. One cane take
photograph in two ways.

9. 1)Complete rotation method
2)Oscillation method.

10. 4)Powder crystal method
In the powder method the crystal sample need not be taken in large
quantity but as little but as 1 mg of the material is sufficient for the
study.
 A is a source of X-rays which can be made monochromatic by a filter.
 Allow the x-ray beam to fall on the powdered specimen P through the
sites S1 and S2.The function of these slits is to get a narrow pencil of
X-Rays.
 Fine powder P, struck on a hair by means of gum is suspended vertically
in the axis of a cylindrical camera.
 This enables sharp lines to be obtained on the photographic films
which is surrounding the powder crystal in the form of circular arc.
 The X-Rays after falling on the powder passes out of the camera
through a cut in the film so as to minimise the fogging produced by the
scattering of direct beam.

11. on the flat photographic plate the observed pattern consists of traces as
shown in fig.

12. Thank-You