X-ray crystallography is a technique used to determine the arrangement of atoms in crystalline solids by using X-rays. When an X-ray beam hits a crystal, it causes the beam to diffract in specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a 3D image of electron density within the crystal. X-ray crystallography uses an X-ray diffractometer containing an X-ray source, monochromator, collimator, goniometer, detector and other parts. It has wide applications in fields like medicine, molecular biology, materials science and more to determine molecular structures.

2. contents
1) Introduction about X-ray crystallography
2) X-ray and its properties
3) History
4) Principle
5) X-ray diffraction
6) Instrumentation
7) Applications
8) Conclusion

3. INTRODUCTION
 X-ray crystallography is the technique of determining
the arrangement of atoms within a crystal, in which a
beam of x-rays strikes a crystal and causes the beam of
light to spread into many specific direction.
 From the angles and intensities of these diffracted
beams, a crystallographer can produce the 3-
dimensional picture of density of the electron within
the crystal.
 Here , we see about history, principle,
instrumentation, uses and limitations of x-ray
crystallography.

4. X-RAY AND ITS PROPERTIES
 An electromagnetic wave of high energy and very
short wavelength (between UV light and gamma ray).
PROPERTIES:
 X-rays travels in a straight line.
 They are electrically neutral
 They are invisible ray.
 They can pass through any materials which are opaque
to light.

5. history
 X-ray crystallography was discovered by JOHN
KAPLAE in the 17th century.
 With the evidence of x-ray crystallography only, Dr.
JAMES WATSON and Dr. FRANCIS CRICK discovered
the double helix structure of DNA.

6. PRINCIPLE
 The vital principle of x-ray crystallography is the
DIFFRACTION.
 The crystal is made to strike against x-ray beam.
 Due to striking the atoms present in the crystal
diffracts the x-ray beam into different diffractions.
 The angle and intensity of this diffraction rays is along
to spatial arrangement of atom in crystal.
 By studying these angle, the 3D structure of any crystal
can be determined.
 X-rays are generated by bombarding electron on a
metallic anode.

7. X-RAY DIFFRACTION
 X-ray crystallography uses
the uniformity of light
diffraction of crystals to
determine the structure of
a molecule or atom.
 They use an x-ray beam to
hit the crystallized
molecule .
 The electron surrounding
the molecule diffract as x-
rays hits them. This forms
a pattern , this type of
pattern is called X-RAY
DIFFRACTION PATTERN.

8. instrumentation
x-ray crystallography uses
the instrument called the x-
ray diffractometer. It has
the following parts:
 X-ray source
 Mono chromator
 Calorimeter
 Goniometer
 Photographic film plate
 Detector.

9. X-RAY SOURCE
 The x-ray tube is the most common x-ray source.
 The tube is evacuated and contains a copper block
with a metal target anode, and a tungsten filament
cathode with a high voltage between them.

10. MONOCHROMATOR
 The word “mono” means
SINGLE and “chroma”
means COLOR.
 The device used to
convert the different color
radiation into single
color.
 It removes the unwanted
rays other than x-rays.
 It produces the x-rays
about 12-24 A*.

11. There is 2 closely packed
metal plate which are
0.3mm apart from each
other.
The x-ray beam
originate from x-ray tube
passes through this gap
and follow single line
path.
COLLIMATOR

12. GONIOMETER
 It is a device on which
crystal structure is to
be determined and
mounted.
 The device spin slowly
in according to crystal
which to rotate on
constant speed.
 It is placed between
the collimator and
photo plate.

13. PHOTO PLATE FILM
 The film captures the
diffraction rays of
crystal.
 The light-sensitive
emulsion of silver salts
was coated on a glass
plate, typically thinner
than common window
glass, instead of a
clear plastic film.

14. DETECTOR
The captured data has
been send to computer
for further processing by
detector where 3D
structure of crystal gets
developed.

15. WORKING OF THE X-RAY
DIFFRACTO METER

16. APPLICATIONS

17. MEDICINE
HIV:
scientists discovered the x-ray crystallo -graphic
structure of HIV PROTEASE, a viral enzyme in 1989
and to prevent the spread of virus in the body.
ARTHRITIS:
To create an effective pain killer that does not cause
ulcers.

18. Atomic science
 The arrangement of various atomic structure of
crystals like salts, metals, semiconductors and many
minerals are identified and studied.
 The atomic arrangement of diamond, graphite like
carbon compounds also studied by x-ray diffraction.

19. Molecular study
 The lattice structure of crystal revealed by diffraction
of the x-rays.
 The bonds like ionic and covalent bonds between
the molecules can be elucidated and studied.
 Molecular structures of the penicillin, vitamin-B12,
insulin, and other proteins can be easily revealed
and studied by x-ray diffraction.

20. DAIRY SCIENCE
LIQUID MILK:
The arrangement of lactose and other mineral
constituents of liquid milk are easily provided by
the x-ray analysis.
MILK STONE:
The atomic arrangement and chemical
composition of milk stone by x-ray diffraction
through photographic film.

21. DAIRY SCIENCE
MILK POWDER:
The study of milk powder is given by analysis of the
x-rays to provide the structural group spacings within
the milk proteins.
Thus the x-ray crystallography is a widely used tool for
the elucidation of the compounds present in milk and
dairy products obtained through their structure and
functional relationship.

22. CONCLUSION
 Thus the x-ray crystallography is used to reveal the
structure of viruses, nucleic acids, and antibodies, etc.
 It is widely used in the atomic and molecular studies.
Hence , the x-ray crystallography has a vast applications
in the various scientific fields.

23. REFERENCE
 X-ray crystallography by JAN DREATH.
 Biochemistry by KUMERASAN.
 www.chem.ucla.edu.com
 www.blogspot.com